pop, pop, pop, pop, pop, pop, pop. i mean, just over and over. >> did you see the gunman? >> i did not. >> you saw two police officers -- >> what looked like two police officers go down. >> was there anything in the protest martha could have conceivable provoked this violence? >> no. no. >> characterize for me the relationship between the 800 marchers and 100 police officers who were there. >> sure. >> how was that relationship going through the march? >> sure, you know, i think people were, you know, for a group of 800 people that were angry about the shootings in st. paul and baton rouge, you know, i think it was a relatively calm environment. even the police were commenting on, you know, just how nonviolent the scene was. and you know, for me, i'm just devastated that some things so beautiful could turn to evil so quickly. >> how would you characterize the relationship between the dallas police department and the minority community? >> i think it is typical. it is tenuous. no question about that. i think, you know, the police are trying to make it better, and i hope they continue. >> why was it necessary to have this protest march? there were several yesterday around the country. >> sure. >> why was this one important to you? >> a lot of anger, and i think people need to have the opportunity to grieve and express their anger in a positive way. this was an opportunity to do that. >> for president obama's reaction, we will go to margaret brennan, who is traveling with the pressed to in warsaw, poland. margaret. >> reporter: good morning. the president is here to tackle national security issues, but twice in the past 12 hours, he has made a public appeal for calm back home. the president called the dallas shootings a vicious, calculated and despicable attack. >> today, our focus is on the victims and their families. they are heartbroken. the entire city of dallas is grieving. police across america, a tight knit family, feels the loss to their core. >> reporter: the dallas shooting happened after the president said was deeply disturbed by recent killings at the hands of police in louisiana and minnesota. on the flight over here, he watched news coverage and decided to speak out, beckihe s none of that justifies targetsing police. the president also said this is a painful reminder of how easy it is to access powerful weapons. >> margaret brennan with the president in warsaw, poland. so in summary today, we have 12 police officers shot, two civilians shot five officers have died. most of the wounded officers have already been released from the hospital. one suspect has been killed. he told police officers that he acted alone, but the investigation is just getting started. back to you in new york. >> scott, thank you. >>> the police killings in dallas stunned police across the country. ahead, how other big city police departments, including the,, >>> gunfire turns the streets of dallas into a terrifying scene. >> get back. >>> witnesses to the attack describe it in their own words. the news is right back here on "cbs this morning." made with real simple ingredients. and no artificial flavors or preservatives. real country fresh taste from real ingredients. welcome to crock country. acids in everyday foods and drinks may weaken and erode your tooth enamel over time. damaged or lost enamel can lead to yellow, dull and thinning teeth. that's why there's pronamel and pronamel for kids. designed to strengthen enamel and help protect against acids in your diet. start protecting your enamel, with pronamel. the #1 dentist-recommended brand for strengthening and protecting enamel. the #1 dentist-recommended brand for strengthening wearing powerful sunscreen? 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[ dryer running ] know what your pets are up to... party's on! ...with xfinity home, connected, protected home. xfinity customers: get a great deal on xfinity home and ask about free installation. call or go online today. see the secret life of pets, in theatres july 8th. >>> south 101 at ygnacio an injury accident blocking lanes slow coming away from highway 37. once you get past that, traffic is clear with no delays from 580 down into san francisco. golden gate bridge no problems. westbound 24 past the caldecott tunnel, look out for a vehicle fire over to the right shoulder. looks like traffic is slow approaching the scene. it improves a lot more once you hit 580 with no delays heading towards the bay bridge. at the bridge though the metering lights are on. looks like you're back to the toll plaza. >> our live weather camera this time around is at sfo. it's picking up a little bit of drizzle and a whole lot of clouds. delays over one hour and five minutes on some arriving flights. 55 santa rosa to 55 in san francisco. also 55 in oakland. winds have been breezy. we'll be variable to 20, 25 during the afternoon hours. 50s beaches, 60s to 70 around the rim of the bay. ample sunshine around the peninsula up to 78 degrees in mountain view. 80s inland. . >>> welcome back to "cbs this morning." we're learning more details about the attack in dallas. protesters were running last night, officers were ambushed during a peaceful protest of this week's deadly police shootings of black men. >> dallas police say five officers were killed. at least seven more officers and two civilians are wounded. police have three suspects in custody. a fourth suspect, killed by a police bomb is identified by a law enforcement source as mika johnson. we learned he was 25-year-old and claimed to be a u.s. veteran. cbs scott pelley continues coverage from downtown dallas. scott. >> reporter: the police chief here in dallas told us that mika johnson, before he was killed, told the police negotiator that there were ieds, as he put it, improvised explosive devices, scattered about the downtown area. so for many hours, before dawn today, police used bomb sniffing dogs to make sure the area was safe. no explosives have been found in the area has been declared free of any explosives. the shooting began last night about 9:00 p.m. local time, at the end of a peaceful protest march. a shooting that set off a scene of horror. >> get down! get back! >> it has been very crazy tonight. it feels leakike a war zone. >> reporter: when the shots rang out, people scattered, and been described as absolute pandemonium. >> the only thing i seen was bullets coming by mean. >> popop, pause. and you see the first two officers go down right by the greyhound station. >> you mean go down like they were hit? >> they were hit. we couldn't see the shooter. the cops had no idea who was shooting at them. at least 50 cop cars went flying by. i've worked downtown for six years now, and i've never seen anything like this. >> don't come this way, because the crowd was coming this way. the mass was coming towards the gunshots. >> it was terrifying experience. >> hearbreaking night in downtown dallas. that's the word that describes it best for the folks that call this place home. >> we as a city, we as a country, must come together, lock arms and heal the wounds. >> reporter: a short time ago, we spoke with pete schulty, a police officer and attorney, who was a friend of one of the officers who was wounded. he told us about how he learned about his friends being wounded, and how he raced to the hospital. >> typical thursday night, having dinner, about 9:00 last night, the pho