the casualties. those numbers will change as we continue to learn more. so if you are just joining us, to catch you up on what has been happening in boston this afternoon, a little bit before 3:00, about 2:50, two bombs exploded near the finish line of the boston marathon that is the aftermath of the first explosion and you will see the smoke of the second explosion at the camera pans left and there it is there, it looks to be about a block away. two explosions in the crowd. there's a still shot of the second explosion that you saw, the one that was down the street. these are apparently both on the sidewalk which was jammed with thousands of people. they were cheering the runners on. this is one of the explosions. we'll put it on a loop for you. there it is behind that blue

fence, hundreds, thousands of spectators. you can see the runner the middle of the road go down because of the concussive force of the blast. boston police telling us two dead, 23 wounded but those numbers tend to be changing. jon lapook has been talking to sources at the hospitals that have been wounded. what numbers are they giving you? >> reporter: tom lang ford, the senior media relations specialist at brigham and women's hospital said 18 to 20 patients, two are critical. and we heard at the mass general there were, i believe, 19 and six were critical. >> pelley: so a number of people in critical condition. we have seen people in the videotape and in the photographs who have apparently suffered traumatic amputation of their limbs boston police said two are dead but as jon lapook report misdemeanor are in critical

condition at boston's best hospitals. bob orr is in washington. he has been talking to his sources in law enforcement in boston. can you bring us up to date on what you've been able to learn. >> scott, we were told there were two device devices that did explode. they had been put in trash cans or garbage containers here in the race route. an area congested with people. if you were targeting a crowd it's the kind of place you could secretly drop a bag care ago device and do bit a bit of damage. we were told that one of the devices that was found that had not exploded is intact that will help decode what was put together but we believe there may have been two unexploded devices that were recovered. there's a little confusion about the police spokesman said -- the police commissioner said at j.f.k. library. we were told a while ago this may have been more like a molotov cocktail, like an

incendiary device and not a bomb. so that's still a little fuzzy. finally the most important thing is what police are not finding. that is when they go to the intelligence reporting stream they're not seeing any claims of responsibility and they're not seeing anything in advance pointing to today as a target or to boston and the marathon as a specific target. that argues that this is possibly the work of a very small group or even a lone wolf. secrets and planning are difficult conspiracies are difficult and when you have something completely off the radar like this appears to be, scott, one of the things you have to consider is it might be the work of a single individual or maybe just a couple. but this is in the early, early stages. they're trying to round up people in the area that may have seen suspicious people in the

area we were told there's at least a surveillance photo of one man carrying what looked to be backpacks so this is fluid and in the early hours as the federal agents move into boston with local police thereunder there to figure this out, scott. >> pelley: bob, thank you very much. as you say, the reporting is very fluid in the news conference with the police commissioner a moment ago. they indicated that a bomb had exploded at the john f. kennedy library but we are also being told from the library people that there was a fire in the a mechanical room there that was just at the same time as the twin bombs at the boston marathon so it may turn out that the j.f.k. library information as we look at it and learn more about it is that it was an accidental fire there at the j.f.k. library just at the same moment exploded. but these were the kind of things that we're going to learn

about as more information becomes available. we do know from the spokeswoman at the j.f.k. library that no one was injured there. whether it was an explosion or a mechanical fire and the mechanical room there at the j.f.k. library we do not know. the police say it was an explosion people at the library are telling us they just suffered a fire at the same moment that the boston marathon was bombed. jon lapook has been talking with people at the hospitals that are receiving the largest number of wounded and, jon, what can you give us on the new numbers? >> they keep coming in and changing. from tufts medical center there are nine people there so if you look at what we know from three major medical centers, there are around 50 people. 19 at mass general, 18 to 20 at the brigham and nine at tufts. >> pelley: around 50 wounded being treated at the hospitals. >> a number of them critical. >> pelley: some of them -- quite a few of them, maybe a

dozen or so in critical condition but others, of course, not so critical in their condition in terms of having lacerations and broken bones. so many, many, many survivors from all of this. boston police have told us that there are two dead that they have confirmed so far. john miller, our senior correspondent, former assistant director of the f.b.i. is with us. john, what have you been learning? >> well, they're looking very hard at that piece of closed circuit television security camera video. they've gotten a individual who they're interested in because he's carrying two backpacks. now you know how early it is and how information will shift and change and that's an important caveat but when you have two devices possibly contained in backpacks and you have an image of somebody moving before that carrying two backpacks that could be someone who's got his backpack and one he's carrying for another runner or that could be a suspect. so what they're doing now between the f.b.i. and boston police department is they're looking at his direction of travel. the shot that they have of him is not really identifiable.

it's from behind. so they're scoping out the network of cctv cameras trying to figure out from the direction he's coming from what other cameras would he have passd? can they identify the same individual this time from the front wand a face. and then based on that look and whatever other cameras they can see from the rest of his trip, can they stitch together where he came from, where he went, did he place these packages and is he a person of interest? that would that would be an extraordinarily big break to have a picture of the person carrying the bombs or it could be one of those leads you run out and find out it goes nowhere. but it's something they're dealindealing with now. >> pelley: but they've already found videotape from surveillance cameras that they find of interest. >> and this is part of the post-blast response protocol, if you will, which is where did it happen, where's the available video, and that critical available video from the moments immediately preceding it when the device might have been

placed and where you can see somebody maybe put it down and maybe walked away. >> pelley: we have jonathan elias who is a correspondent for our station wbz in boston. jonathan, i understand you were there when it happened. can you tell us what you saw? >> scott, we were 30 feet away from when this blast went off. we were standing at the finish line. it was a photographer, producer and myself. everybody was in a great mood, great race, the weather was perfect and i pulled out my camera on my phone and told our photographer "smile" and took a picture and as soon as he turned back around to face the finish line this explosion went off 30 feet -- when i say 30 feet it was like right across the street. that kind of direction. big plume of smoke. clearly whatever went off was sitting on the sidewalk because the smoke went straight up. it didn't come out from the buildings. glass was shattered in four or five buildings right next to each other. we ran toward the direction because we weren't sure at first what happened and then a second explosion two blocks up went off and that's when we started running towards where the first bombing happened. every at that point was running

past us to get out. the officials for the race were about six to seven blocks up. they were stopping the race and telling the runners to go away. people were running into the runners to get away from this part of town. when we got over to the sidewalk, it was horrific. there were people lying on the ground, nobody was screaming, nobody was crying, it's almost like their eyes were open and nobody was there. they were completely checked out in shock. people had been blown apart in some cases, i don't mean to get too horrific but the scene was absolutely horrific. our photographer was helping tear down the barriers to so paramedics and emergency personnel could help them. not more than a block and a half away there's a triage tent to take care of runners that come in that maybe have strains or shortness of breath but everybody came running out of that tent with wheelchairs and gurneys and they were picking up the wounded, getting them into the tent, they were trying to maintain or trying to sustain them before they can taken a ambulance ride to the hospital. but keep in mind, all this is happening at the same time that everybody doesn't know when another device might go off.

so, in fact, the police had to come through the triage tent and do a sweep while they were working on the wounded and the ambulances came in, the police shut down -- this is the heart of boston. the copley center here, this is the heart of boston. this is all shut down now. no traffic in or out. our governor just got on the air and told people "if you were thinking about going out, don't. stay home. if you here in a hotel, go back to your room." and just to give you some perspective, scott, lets me show you. on the sidewalk here, the runners would be running down the street. the bomb went off on this sidewalk and not more than maybe 15, 20 feet away, that's the street. those were the runners coming past the bombing. so we can't account for who was hit? were runners hit or was it just spectators that were sitting on the sidewalk? i guess if there's any silver lining in any of this, that sidewalk probably an hour earlier was absolutely packed ten deep. but because we were in the fourth hour of the second wave of racers, we'd already seen the finishes by the men and women, basically it thinned out. had that happened an hour or two

hours earlier the numbers we would be looking at would be greater than that. but there isn't any silver lining here right now as the investigation as you know, scott, you just heard john talking about, is in its very initial stage. >> pelley: jonathan, one of the bombs exploded very near the finish line. can you paint that picture for us of who was there and what is there? >> okay, so if my back is to the grand stands-- this is just on boylston across from me, our back literally was to the grandstand. the finish line would have been right where that guy is standing right there. people were running across the line. and for marathon runners they were jubilant. they were coming across, raising their hands in the air, so ecstatic they finished the race. so this is where we were standing the, grandstand behind me, the finish line here and just across the street the same distance from this street here you had spectators lining it with signs looking for their loved ones coming across the finish line cheering them on for that final leg. and that's what happened.

the bomb literally went off across the street. at first people were sitting around saying what just happened. our infrastructure here in boston is old, perhaps it was a manhole cover that blew. but then a second later there was a second bomb that went off two blocks away and that's when everybody got the picture loud and clear. people were sprinting past us and all of the emergency personnel were running towards us. and it was just absolutely kay kwrot thick n that final minute. i will say this: the police here in boston, they reacted so professionally. in those first few minutes i even heard officers yelling as they're running to help those that were wounded they were yelling "this is a crime scene, be careful, let's secure this area. it's a crime scene." so they were already working in conjunction with not only helping the wounded but understanding this was a crime scene and they needed to preserve whatever they could find at that location. >> pelley: jonathan, the first explosion occurred at the finish line there as you just described. the second explosion was a block or two away. what was in that location? >> well, again, i wish i could

-- it's not as clear but let's just say this street right, this is st. james street. boylston is a big four-lane kind of wide street and that is the finishing straightaway for the marathon. coming down that street it's -- i've got to say maybe three quarters of a mile, maybe a mile straightaway and when you come down that area, that's what it was. it was all the track. that's where all the runners were. so two blocks up from the finish line again spectators line both sides of the street, they are packed in there. but, again, it had thinned out from the spectator standpoint but you had a lot of runners on the track and this bomb clearly affected the runners because it knocked people on to the ground. the only thing we didn't see-- let me check with chris-- we didn't see anybody on this side of the fence, so that would have been the runners. all the victims were on the sidewalk. at this point it looks as though most of the spectators were the ones impacted by the blasts. >> pelley: jonathan elias of our station wbz in boston. jonathan, thank you very much. we are looking at new videotape coming in.

this occurred just shy of 3:00. it was about 2:50 eastern time when the boston marathon was attacked today by two bombs that exploded, one near the finish line, one a couple of blocks from the finish line. at least two people have been killed. many have been wounded we understand there's something on the order of 50 people being treated at the boston hospitals. some of them are in critical condition. the first explosion occurred just before 3:00 and the second explosion followed. this is a still photograph of the second explosion. this followed by only about 15 seconds or so thousands of people lined this route cheering on the runners.

this is the explosion near the finish line right there. it's a very short piece of videotape that's behind the blue fences where all the spectators. you see the runner in the middle of the frame falling down to the street just from the concussive force of the blast that occurred there. the police have now confirmed for us there were two bombs that were detonated at the boston marathon. a bomb was found nearby and the boston bomb squad diffused that. at a news conference a few minutes ago the boston police said there had been another explosion at the j.f.k. library in boston however we're getting more information on that. the library said it suffered a fire, an accident in its mechanical room there and that no one was injured in that

accident. so we have those conflicting reports at this how shall from the library. the police said there was a bomb there. people at the library said they had an accidental fire which just happened to occur at almost precisely the same moment the boston marathon was attacked. john miller, our senior correspondent, former assistant director of the f.b.i., give us a sense. you know this like almost no other. what's happening at the f.b.i., at the federal level? how are they mounting this investigation now. >> well, the first thing that will happen is from sigh on, the command center, they will send out several bureau-wide instructions to all 56 field offices. the first one will be everybody in every field intelligence group go over all your human intelligence and look for anything that might be relevant to this. the second thing they deal is if it's not in the reporting go

find out if it exists out there somewhere else and that means across 56 field offices if you are a human intelligence source of the f.b.i. on terrorism you're going to be getting a call or a visit from your handler, agent right now and they'll be saying what do you know? what have you heard? can what can you find out? that is the human piece of this. the electronic piece will be just as significant. they're on the phone right now with the national security agency, the c.i.a. and the defense intelligence agency saying go over every single wire that was recorded over the first 48 hours going backwards from this listen live to everything puck in the 24 hours going forward then go backwards from that if you have to. but what we're going to be looking for is was there some coded communication from some known terrorist group that would give them a sign here? now i say that in the context, scott, that it is possible as we learned in oklahoma city that while the focus is on international terrorism it could

be a domestic incident, the work of a lone wolf and so on. but they're not going to wait for that to settle. they're going to throw out a dragnet for information, start pulling it in and getting very intensive analysis while they look for evidence. >> pelley: bob orr was reporting from washington earlier that there is at least this point no credible claim of responsibility for twin bombing in boston. we've been watchin watching this videotape of the immediate aftermath of that explosion near the finish line and i wonder if in just a moment we might be able to take that back to its very beginning and just listen in to what has happened. this is one of the first tapes that has audio on it to give us a sense of what was going on in those first moments so if we could take that tape back to its beginning perhaps we could get a

sense. >> hey! >> we need help! >> oh, my god! oh, my god! >> we've had an attack. oh, my god, oh, my god. oh, my god!

oh, my god. oh, my god. >> pelley: this was the scene just before 3:00 eastern time when two bombs struck near the finish line of the boston marathon. this is unedited videotape. boston police have confirmed that two are dead, at least, and we have confirmed with the

various hospital emergency rooms that there is something on the order of 50 people who have been injured. some of them are in critical condition. here you see some people who were near the blast wounded but conscious, in shock. one reporter described an eerie sound of silence. perhaps not what you would expect but he said the people were so dazed by the explosion that for a long time even the seriously injured did not realize what had happened to them. we have seen some evidence of traumatic amputation of limbs in the videotape that we've brought in to the newsroom. many people in critical condition. the mayor of boston is expected to hold a news conference live in the next few minutes and as soon as he comes to the podium we will switch you there directly to get new information.

what we do know at this point is that at least two bombs exploded at the boston marathon today. a third bomb was discovered and disarmed by the boston police after the first two went off. in a news conference-- that's a picture of the second explosion you see in the distance-- the smoke rising in the foreground then smoke rising about two blocks away. the two bombs went off about 15 seconds, one after the other. in a news conference we heard a short while ago boston police said there was another explosion at the j.f.k. library. this is a confused situation. it happened about the same time but people at the library believe there is reason to believe it was an accident.

but the j.f.k. library has confirmed they have no injuries there. whether it was an simultaneous accident or whether it was another explosive device we do not know and may find out from the mayor here as he speaks to us shortly. jon lapook has been talking with various emergency rooms in the area and john i wonder if you can give us some sense of how many people are being treated, how serious their wounds are and what kinds of things they're suffering from. >> we have three hospitals, we have the mass general that has 19 patients, six of them in critical condition. then we have the brigham which has anywhere from 18 to 20. tufts has 9. i just spoke to a friend of mine at another hospital, they're all rolling into the contingency plans but they're ready for other people to come. i don't know how many people will get it but it's impressive. we heard about how prepared the police were. the hospitals had these plans. we heard about the amber plan at the brigham.

they are ready to roll this out. rehearsed this. >> pelley: john miller, former assistant director of the f.b.i. this is terrorism it would seem. we don't know if it's domestic as in the case of oklahoma city or whether it's a foreign-inspired plot. >> so when you look at it you have to consider what did it take to put this together? some of the basic indicators are multiple devices placed at a high profile event where there was a good deal of security to start with. is what we're seeing when you look at those pictures of the devices going off is you're seeing -- you see a big flash, an explosion, a lot of white smoke which a bomb tech might tell you could be indicative of a low explosive as opposed to a high explosive. you're seeing devastating injuries to lower extremities which is indicative as we saw in the 7/7 bli& in the subways in london of a backpack type device

placed on the ground or device placed in a trash can low to the ground. where that blast goes out in an open air environment and hits people. but the key here is the fact that somebody was able to carry these devices in, place them and time them to go off within 15 seconds of each other and that there may as we're being told have been a third device. so a lot of thought went into this. when you think of where does this kind of planning art come from all you have to do is go back to the latest issue of "inspire" magazine which is the magazine published by al qaeda of the arabian peninsula and what they were calling for in that issue was rather than rely on the front office of a terrorist organization, they were inspiring, if you will, true to their name followers around the globe but particularly in the united states to learn the recipes for explosives from the magazine, learn the elements of the plot.

when we heard that there's been no claims of responsibility, more indicators that point towards-- and, remember, this is all very early-- a domestically put together plot, the so-called lone wolf or maybe two people acting together. we're the only ones they're -- where the only ones they're communicating with is either themselves or the other person in the group and that's just the kind of plot that is likely to fly under the intelligence dragnets' radar because it's not communicating with the front office of a terrorist group or doing any of the other things that would make it pop up on the radar. so that is one of the first things they'll look at in the absence of other information that it's something closer to home. >> pelley: thank you, john. we do not know, of course, whether this act of terrorism

was inspired overseas or here in the united states. we don't know any information the police may have with regard to this attack on the boston marathon but what is quite clear that two bombs were placed where they would do the most harm, where they would strike innocent men, women, and children who were jammed near the finish line to watch the end of the boston marathon today. we have a new piece of videotape. i am told that what you want to watch for is the sound of the bomb in this videotape. it's very brief but apparently it was captured and we'll play that for you now. >> whoa! >> something just blew up! (screaming) run! go! >> pelley: that would have been a second blast. you heard the woman say "something just blew up" and

then 15 seconds later we know a second bomb went off. so that would have been the second blast that you heard in that videotape. let's listen to that one more time. >> whoa! something just blew up. (explosion) (screaming) run! go! >> pelley: the second detonation at the boston marathon. that was just before 3:00 today eastern time. two bombs exploded, at least two people have been killed. something on the order of 50 people are being treated at various hospitals, many of them are in critical condition, some not so seriously wounded. jon lapook has been talking to the hospitals. jon, what do you know now? >> i got another new piece of information from boston children's. we have four patients ranging from good to serious, no fatalities there. no more coming in but they will be taking the overflow from the brigham where there are 18 to 20 and two are critical there. at tufts there are nine patients, none of them are -- we don't know the status of them

and at mass general 22 confirms, six critical, two serious, the rest are being evaluated. we know the injuries range from anything from superficial cuts from the glass or whatever to we know at least one person with a ruptured eardrum. we saw at the very beginning of that blast everybody covered their ear and when you saw the concussive blast knocked down at least two people. so we can expect there to be more problems with people's hearing and ruptured eardrums all the way to a severed limb, we know there was one eyewitness about and then, of course, more serious than that. >> pelley: jon, thank you. major garrett is at the white house. he's been following events for us there. the president was informed earlier today. major, what do you know now? >> well, scott, we've been told by a white house official that later on this afternoon-- not too long ago-- the president received separate briefings from the f.b.i. director, director robert mueller and the department of homeland security secretary janet napolitano. now, the white house has just released a still photograph taken here at the white house not of either of those two briefings but of a phone call

the president placed earlier just after being informed of the explosions in boston. that's a phone call he placed to the f.b.i. director robert mueller. the white house says the president is receiving regular updates on this, but the briefing from robert mueller and janet napolitano, the secretary of homeland security, the most recent information we've received from the white house specifically about who was informing the president and for the first time, scott, the white house describes this as an active investigation. it doesn't call it an active terrorist investigation, an active criminal investigation but, quite obviously, based on everything that we are reporting, it is an active investigation, the white house now calls it that for the first time. and one other note, scott, it's important to suggest or let our viewers know that there was no crisis atmosphere here that derailed the president's schedule. at 4:30 he was to have a very typical ambassadorial yes ken -rbl i ceremony in. the president did not completely disrupt his schedule this

afternoon. he received regular briefings, the most recent one we've been informed of, from the f.b.i. director and the secretary of homeland security. >> pelley: major gator at the white house. eric shapiro in the control room, eric i'm going to ask you to cue up the videotape you were showing us. we were listening to major dwaret. this is tape of the victimo victims on the sidewalk in the aftermath of the explosion. let's listen in on what's happening in this, the immediate aftermath of the 2 ( sirens prospect sirens )

>> hey! there's got to be people hurt! >> we need help! >> pelley: just before 3:00 at the finish line of the boston mar thorn two bombs exploded in the crowd. at least two people dead, although that number, sadly, slykely to change as we learn more. something on the order of 50 people in the hospital being treated for a variety of wounds, some of them in critical condition. we have a number of photographs of the bombs actually exploding. this is, of course, a very well-covered event. this is the finish line at one of the greatest races in the world, so there were many cameras there. one photograph is a still photograph-- let's look at this one first.

this is near the finish line. this is the actual blast itself. there it goes. behind that blue fence, hundreds, probably thousands of spectators. you see from the concussive force, this runner in the middle of the road, falling down. you get a sense of how powerful that was, and to go off in a place that was packed that way. so many people injured, at least two killed. this is the second explosion. this is still photograph of the second explosion. these are runners at the end of 26 miles at this point with the finish line down the road. you can see it, with the finish line in sight. this is the second explosion, which occurred about 15 seconds after the first one. and finally, we have these images of both explosions that were caught on videotape. that's the first one, the smoke clearing from the first explosion. and as you watch down the street, the camera will pan left again, you'll see the smoke from the second explosion. and there is it is. the sound of the second

explosion was captured in a short clip of videotape, and we'll play that for you now. >> something just blew up. >> run! go! >> pelley: you could hear the woman said that something just exploded. and then you hear that second explosion. boston police have told us there were at least three bombs. two of them exploded. a third bomb was discovered by the police and was defused. there has been some confusion about an event at the j.f.k. library in boston which occurred at the same time, right about 3:00. in the news conference we heard a short while ago, the onc boston police were saying they thought another bomb exploded at the library, but there is now an indication from the library and officials that the library simply suffered some kind of an accidental fire at the same moment, and the library people

have confirmed to us that no one was hurt at the j.f.k. library. this appears to be an event centered on the boston marathon. there is no indication that there is a wider plot afoot, nothing else that we know of has anywhere else in the country. although, standard security protocols have gone into effect. there is more security at the white house. the new york police department has ramped up security all over the city. and david martin tells us from the pentagon, that the air force is planning on sending aircraft to secure the airspace around boston. we have new video coming in right now of the first explosion, this one near the finish line. let's have a look and see what this is.

and that was the second-- that is the second explosion you heard right there. this is video that we have received from the "boston globe "" newspaper. >> hey, there have to be people hurt out there! >> pelley: we're going to go back to the bing of this videotape. this is the first time we have seen this, and here it is again. that's the second explosion. about two blocks away.

>> hey! there's got to be people hurt out there! >> we need help! >> pelley: that was about 10 minutes before 3:00, eastern time. boston marathon was in its fourth hour, many of the best runners had already crossed the finish line, many hundreds were still coming up the road. right here at boylston street. first explosion was followed by a second one about two blocks away, also in the crowd.

we do not know who did this or why. but the bombs were clearly set to kill and maim as many innocent people as possible. both bombs were placed in the thick of the crowd as people cheered on the racers at the conclusion of the boston marathon today. we are expecting a news conference any moment from the mayor of boston. we'll have new information from the mayor shortly, and as soon as that news conference begins, we will switch you there. there's been a lot of conflicting information over the last two and a half hours, as there always is in situations like this. but here is what we are most confident in right now. clearly, two explosions, two bombs. a third bomb was found in the vicinity of the boston marathon

route. and it was defused by the boston police. now, there was a third explosion at the john f. kennedy library at the same time, but now we are being told that was not a bomb. the police news conference that was held a while ago suggested that there was a bomb at the j.f.k. library. we are being told now that there was a fire in a mechanical room at the library, just happened to be at the same time that these bombs went off, and we are told by the folks at the j.f.k. library that no one was injured there. but we coknow fro co-- do know from the boston police, at least two people have been killed. that number will likely grow as we learn more. and at least 50 people are in various emergency rooms in boston. many of them are in critical

condition. most of them have survivable injuries. a great deal of trauma, broken bones, bleeding a major concern. these pictures were shot about two and a half hours ago, immediately after the bombing, but we are told now the scene is completely cleared. the entire area, part of the heart of boston, is a crime scene, and federal agents, state agents, local police, will be combing through every inch of these blocks looking for any type of a fragment of a bomb that they can use in order to find the perpetrators of this terrible event. jon lapook has been keeping up with the casualties in the hospitals around boston. jon, bring us back up to date, if you would, on the numbers and the types of injuries that are

being treated. >> reporter: well, the types of injuries range everywhere from cuts to we heard an eyewitness report of an amputation. i know of at least one person who has a ruptured eardrum. they sound less serious, but with that concussive force i'm sure there will be more injuries like that. with the deathes, we know there will be a lot more serious things happening in the future. at the mass. general, we have 19 people there. at the brigham, 18-20. at tuftes, nine. and then five at another hospital. so we're talking about the mid-50s right now. and i have a report from tufts, as a precaution, the boston police department has temporarily evacuated the emergency department. patients have been safely moved. the rest of the hospital is open as normal. as soon as they'll be able to move the patients back to the emergency department we will let you know. >> pelley: no information on why they took that action? >> no, some sort of precaution. >> pelley: we have a photograph now, an official photograph from the white house

of the president as he was notified of this act of terrorism in boston. this is the president talking worky understand, to the f.b.i. director, director mueller. we could presume director mueller at this moment is in his command post there at the f.b.i. headquarters. there is a very large and elaborate command center set up for the f.b.i. to deal with exactly the kind of event that we have seen happen today. an act of terrorism. by whom, we do not know. but two bombs targeting the boston marathon. it was a short while ago that we received the first videotape of the first bomb exploding near the finish line, a videotape that also capture the second explosion. you see boylston street there. you see the finish line, the first bomb was right next to it, and here's that bomb exploding.

( screams ) and that was the sound of the second bomb. about two blocks away. this video has come to us courtesy of the "boston globe." northern command, the part of the pentagon that covers the united states, was thinking of flying combat aircraft over boston to make sure that the airspace there was secure, but we are told now that northern command has decided nostand that down, so they are not sending the aircraft at this point. apparently, some indication then that the pentagon and our national intelligence community

believes that there is not a threat from the air of any kind, no reason to believe there would be. it was just a precaution that they were planning but have now decided to stand down. >> oh, my god. oh, my god. oh, my god. oh, my god. >> pelley: a number of witnesses have told us that they saw people who they believed had been killed. the boston police department has said two are dead. but we do expect to hear more from the mayor of boston who will be having a news conference shortly. i want to recap and correct some information that we heard earlier one more time.

in a news conference with the boston police, about an hour ago, they suggested that there had been another bombing at the j.f.k. museum quite some distance away. and we now understand-- we now understand that, that was a fire, an accident that occurred at the library in a mechanical room about the same time that these bombs went off. so there was confusion about that as there would be. the library tells us that no one was hurt. so now we know there's no indication of a terrorist attack at the library. this appears to be centered on the boston marathon. three bombs, at least, two of them exploded. the boston police are telling us that they a third bosms discovered and defused, and they now apparently have that intact,

which will be a wealth of evidence for the ongoing investigation. the president is going to brief reporters at the white house at about 10 minutes after 6:00, eastern time. and, of course, we will bring that to you live when the president has an opportunity to come out. those times are likely to slip because this is an emergency situation, and things are changing all the time. john miller, our senior correspondent and former assistant director of the f.b.i. has been talking to his sources. john, what are you hearing now? >> reporter: more of the same, scott. just that they're putting together this operation out of the boston field office of the f.b.i. they're coordinating that with headquarters, and they're really sending that out in ripples through the entire intelligence community. withdrew got 16 intelligence agencies that have just come to a near full stop today in terms of this incident, and comb through what you've been seeing and hearing and look for anything that relates to attribution here.

are we dealing with a domestic incident? are we dealing with a loan wolf? are we dealing with something inspired by a terrorist group from overseas or operated overseas, and right now that's coming together slowly. >> pelley: no indication yet on who did this, whether it was a foreign terrorist plot or a domestic terrorist plot. >> reporter: now, but you can see by the construct of this plot, at least two-- and it peers now probably three devices -- set to go off almost simultaneously at a globally covered and televised event that this has all of the hallmark of somebody who sat down and planned this out for a maximum effect. >> pelley: designed to get attention. >> reporter: it was designed to get exactly the kind of attention we're seeing now. that's step one. but as bob orr has pointed out, our national security correspondent down in washington, part of getting the maximum effect of attention is the theory of terrorism is that

it is theater. it is meant to put on a specticle. it is meant to garner lots of attention. it is meant to contain calma. a terrible kind of theater meant to inspire fear. but the other part of that is, it has to come with that second piece, which is why are you doing this? who are you? and why are you doing this? and what we haven't seen now is the carefully planned claim of responsibility that would have come on videotape or in a martyrdom video or in some other video from a foreign terrorist organization. what we also haven't seen yet-- and i'm sure we will in some time-- are the predictable false claims of responsibilities on the parts of groups that had nothing to do with it. that's why the-- really, the intelligence community has gone into overdrive to try to figure out what they either can see in the intelligence that's come over the transom in recent days or what they can squeeze out of their human and signal sources now. >> pelley: we are expecting a

news conference from the mayor of boston at any time. we are expecting to see the president at the white house at about 10 minutes after 6:00 eastern time to tell us a little bit more about the federal response and what the president may have been told up to this point in time. if you are just joining us, there has been a terrorist attack in boston at the boston marathon. two bombs were placed in the crowds designed to wreak maximum death and maiming of innocent people. we have a number of videotapes of the explosion because, of course, this is a very heavily covered event that's the second bomb you see about two blocks down from the first explosion. they blew up with 15 seconds apart. let's-- this is a still photograph of the second bomb exploding. and you get a sense of where both of these devices were

placed. they were in the crowd on both sides of the street, thousands of people were cheering the runners on. you see the runners there in the middle of the street. they're running toward the finish line. they're 26 miles into this. and so thousands of people, both sides of the street, cheering the runners on, when the explosions occurred. this is a little bit of an arial view of boylston street down at the bottom of the frame is the finish line. you see where the first explosion was. the second explosion about 15 seconds later occurred up the street. two bombs there, that exploded. police say that there was a third bomb that they discovered. this is the explosion of the first bomb. now listen for the second one. ( screams ) ( explosion ) >> pelley: and there is the second explosion.

let's listen for just a moment. >> hey! there's got to be people hurt out there! >> we need help! >> oh, my god. >> pelley: at least two people have been killed, but that was an early report from the boston police department, and, unfortunately, in these kinds of things, that number is likely to grow. more than 50 people are reported in various emergency rooms in the area. many of them are in crack condition. there has been some traumatic amputation of limbs on the part of some of the people in the crowd. other people have been wounded but not as gravely. >> oh, my god. oh, my god.

oh, my god. >> pelley: we were just talking to john miller about some of the possibilities regarding foreign terrorists and our bob orr has been talking with his source about the possibility of domestic terrorism. he's in our washington bureau now. bob. >> reporter: scott, we have to say at the outset, we have no idea who is behind this. the list of suspects is open ended. it could be al qaeda. it could be somewhat influenced by al qaeda, or it could be a domestic loan wolf or domestic group. one thing we have to raise is we have to look at the calendar. today is april 15. most of us know that as tax day. it's also called patriot's day. it's the beginning of the third week of april eye would be interested to see what john things-- in the past it has been a troubled week in this country in terms of extremists, both on the left and on the right. the biggest events have happened

with right wing domestic extremists. the waco siege, for example, in waco, texas, came down in a fiery end on april 18 and 19. oklahoma city, the bombing by mcveigh and nicholes, happened on april 19, the same date in 1995. i'm not saying that those things have anything to do with this, but over the years, frankly, this has been a week that's sometimes unnerved law enforcement because there are sympathizer sympathizers and there are radicals who in some twisted ways sometimes think about commemorating those awful events. this is a wide-open field of potential suspects ranging on the one hand from some kind of domestic group, to maybe just one egreed individual who had times to make had devices and distribute them. we assume this may be a small-cell plot because these devices went on sequentially. that's assuming all the timers were precise, and the timing of the blast, scotts, we don't know, may have been in some ways

coincidental. these are the kinds of things investigators have on the table in front of them at the command centers of the f.b.i., and a.t.f., as they try to figure out where this might go, scott. >> pelley: bork you told us a couple of hours ago that there was no credible claim of responsibility. is that the still the case as you know it? >> it's still the case, and that's important. not only no credible claim coming behind the event, but also there is a notable lack of chattener the intel world, people talking about this who might have some nefarious background or intent. so that's kind of interesting. whoever is behind this, whoever planned it apparently did it off the radar. that argues, in one sernings perhaps for a lone wolf, somebody who got an idea, maybe out of a magazine pour someone who had their own grievance and went to the internet and learned how to build a bomb. or it might be a mod welsomeone had some help. i think in some form, scott, the

failed attempt when shazadd, a man trained by the pakistani taliban, drove an s.u.v. loaded with explosives into times square, only because it was a poorly constructed bomb did that not cause a great deal of carnage. that was a case in which shazadd was a lone wolf but had help, guidance, and training from a bona fide terrorist organization. if you look at the international spector, as we wrap up the possible scenarios here, the most recent attempts from al qaeda have come from a group in yemen, al qaeda in the arabian peninsula, and they have been on a much grander scale. they tried in 2009 on christmas day to bring down an airplane with the so-called underwear bomb. en and this the following august, they tried to bring down a couple of cargo planes, with bombs hidden inside printers. any of these groups and/or people could be suspects and right now, frankly, i don't

think the authorities have a great deal to go on. john. >> reporter: bob, one of the things that you look for in these things is that claim of responsibility. have we heard any claims that have been floating out there yet, and whether or not they're deemed credible or not? >> reporter: now, as we've been discussing for a while, there's nothing so far that's coming over the transom that they even looked twice at. the intele guys have been on this, as you know, better than any of us. they have been on this since it happened about 2:50 this afternoon. they have taken a look at what happened since event. they have rescrubbed want events leading up to the event and they don't see any markers, nothing that points them in any one particular direction. so, again, the absence of two things, the absence of intele, or even a quasi-specific threat on the front side, the absence of a credible claim on the backside seems to argue for something either very closely

held-- and you know conspiracies and secrets are hard-- or it argues for someone who perhaps acted by themselves or with one partner, something like that. >> reporter: and it certainly goes towards that model which al qaeda has been advocating in their communications, which is-- which is to inspire the lone wolves. but let's go to massachusetts governor deval patrick, in a preference conference now. >> ...at the usual meantime-up place because the race was cut short. we'll be in a position to announce that, we hope very shortly, so people can find-- some assistance to help people find their loved ones. but i really am grateful that all of the federal, state, and local law enforcement officials are coordinating so closely and so well. they are talking constantly. we are all in investigation mode right now. it's a very serious time, so we do need people to stay out of

area of the explosion for the time being. >> reporter: governor deval patrick of massachusetts, reiterating a request by police for people to stay out of the area, as police do what they earlier told us, to try to stabilize the area where they're trying to clear many suspicious packages, mostly innocent material that people just dropped and ran away from after the explosions, but things that are backpacks and other things that need to be checked out nonetheless. dr. jon lapook has been following its situation at emergency rooms around the greater boston area. do we have an update on casualties, injuries, new numbers? >> reporter: jon, the numbers at least starting to stabilize for this first wave. remember, in the second wave, people who weren't brought there can report to the emergency room so this number may go up later. right now there are 22 people at mass. general, six critical. at the brigham, there are 18-20, two critical. at tufts there are nine.

and at children's hospital, there are four. >> reporter: now, there's something else going on at tufts. what do we know about that? >> reporter: well, originally they evacuated the emergency room for i guess precaution, and i just heard a few minutes ago they've brought the patient backs in. something happened there, some signal, or maybe an over-abundance of caution that they actually evacuated the emergency room. >> reporter: so they are back in business. at this time in boston, investigator investigators are together. the special agent in charge of the boston field office of the f.b.i., ed davis, the police commissioner, the commander of the massachusetts state police. and they are trying to put together their long-range investigative plan for as long as this is going to take, but, of course, also what are they going to do over the next 24 hours as they deal with this situation, which is still rather fluid as this information crystallized. >> reporter: i just heard, the emergency room we now k