#asking for a friend. his wife hillary is running. we'll see you back here at 6:00. on this monday night, gang warfare. 170 people facing charges after a gun fight leaves nine dead, 18 wounded. a horrific scene. authorities have never seen anything like it. hacking a plane? a computer expert and what he says he did from his seat and what the fbi is telling us tonight. mansion murder mystery. who killed a family inside their home and set it on fire. tonight, bizarre clues are emerging as police hunt a person of interest caught on camera. tragedy at yosemite. the death of a legendary daredevil who rose to fame by living life on the edge. what went wrong on his final jump?

"nightly news" begins right now. from nbc world news headquarters in new york. this is "nbc nightly news" reporting tonight. lester holt. good evening. police in waco, texas, had a lunch a planned weekend gathering of bikeer gangs would go bad, but nothing like the violence that broke out before their eyes. gun fire, stabbings and beatings as members of criminal gangs waged battle with each other and turned on police in a restaurant parking lot. when it was over, nine people were dead, 18 injured, 170 arrested. tonight we are learning more about the groups involved as police brace for possible retaliation attacks. our national correspondent miguel almaguer is in waco tonight with the latest. >> reporter: police called the crime scene at the twin peaks bar & grill among the most violent and gruesome they have ever seen. a brawl between five rival motorcycle gangs leaves nine dead and 18 wounded. >> at last count we have 170 individuals that we have arrested.

those individuals are being charged with engaging in organized crime in reference to the shooting at twin peaks which is a capital murder. >> reporter: what started as a fistfight in a bathroom turned into a rumble, with brass knuckles, knives, chains and clubs before the wild shootout poured into the parking lot. >> we were panicked initially. you know, when a man ran are in, everybody -- a lot of people started ducking. >> reporter: innocent diners caught in the middle. more than a hundred weapons recovered. >> nobody was doing anything. they started shooting people. i don't know what the problem is. >> reporter: with gangs under surveillance, police in the parking lot responded quickly. incredibly, no innocent bystanders hurt. >> this can happen in any town across the united states. unfortunately they chose to be here on a sunday in waco, texas. >> reporter: with the

tellevision drama "sons of anarchy" pop la rising motorcycle culture investigators jay dobbins who infiltrated the hells angels say they often battle over drugs and turf. >> it is a nasty, dirty, bloody, vomit-covered existence. there is nothing sexy about it when you're in it. >> reporter: motorcycle gangs like the bandidos, said to be behind sunday's shooting, are as dangerous as ever. >> the bandidos are an international organized crime syndicate. these events that we saw yesterday in texas, they happen all the time with these guys. >> reporter: tonight with motorcycle gangs vowing retaliation, police say their officers have now become targets so they have stepped up patrols. officers have been critical of the restaurant management here saying they were warned of the potential of violence and did nothing to stop it. management said they were working with police, but the franchise owner, the

corporate owner seems to agree stripping the franchise of the franchise title is. >> miguel, thank you. tonight, as amtrak resumes full service up and down the northeaster corridor for the first time since the deadly derailment in philadelphia, there are new turns in the investigation. the feds weighing in on the theory that something may have struck the train moments before disaster. nbc's tom costello has late details. tom? >> hi, lester, good evening. the key questions are why was the train speeding, and was it along with two other trains hit by a projectile minutes before 188 went off the tracks? tonight, the fbi says the shattered glass on the derailed amtrak train was not caused by a bullet, but the ntsb hasn't ruled out that another projectile was thrown at the train, possibly disorienting the engineer who was new on the tracks. two other trains may have been hit. in philadelphia this morning -- >> you were the first this line? >> first one. >> first one in line gets a hug.

>> oh, yeah! >> reporter: the mayor was on hand as the first passenger s left for new york. 40,000 amtrak passengers traveled the northeast corridor every day. with the line shut down since tuesday most were ready to climb aboard. >> i trust amtrak executives and all the amtrak people would not put us on the trains if they didn't think it was safe . >> i'm sure they have done the work and installed the right equipment. >> reporter: clearing the wreckage posed one of the biggest challenges in 20 years. ceo boardman telling me new government ordered safety upgrades are in place. >> everybody on the railroad is emotional about this. it's focused and committed to safety. this is a safe railroad to ride. we know it. >> reporter: among safety upgrades an automatic braking system along the stretch of track that until the crash had none. as we saw firsthand, a new speed limit for trains in the year of the disaster. we have really slowed down here. this is the s-curve where train 188 derailed after doing double the posted speed limit. the new rules require engineers to come into

this curve at 45, down from 50. engineer brandon bostian has told investigators he can't remember the events leading up to the crash. meanwhile today, funerals for three more victims. laura finamore, rachel jacobs and bob gildersleeve. today an assistant conductor last week said maybe she heard something over a garbled radio channel that maybe the engineer was, in fact, reporting he had been hit, maybe by gunfire. thousand the ntsb says there was no recording of any such radio traffic and all radio traffic is recorded. lester? >> tom costello, thank you. a major move by president obama drawing a line on heavy duty military-style equipment used by local law enforcement after the nation witnessed scenes between protesters and police who were looking more like soldiers on american streets. there were questions about whether it would tie the hands of police in some instances. ron allen has more.

>> reporter: after months of confrontation on america's streets, president obama today banned the federal government from giving some types of military equipment to local police. >> we have seen how militarized gear can sometimes give people a feeling like there is an occupying force as oppposed to a force that's part of the community protecting and serving them. >> reporter: prohibited equipment includes tracked armored vehicles, weaponized aircraft, grenade launchers. on the restricted list, armored vehicles, riot gear, specialized ammunition, only available if approved through a very rigorous process. in ferguson, we saw tactical officers in a bearcat, an armored vehicle able to with stand impact from a .50 caliber machine gun. a precision rifle with a range of 500 to 800 yards. the police warned the protesters to clear the area. the protesters say they are not going anywhere. the police are starting to move in. >> reporter: nationally some 600 mine resistant

vehicles are in use. humvees, machine guns, camouflage, helicopters and planes. much of it acquired after 9/11 as local police became the front line in the war on terror. >> if a helmet and camouflage fatigues are aggressive, i think bricks, bottles and sticks are just as aggressive. >> reporter: police point out dozens of officers were injured if baltimore. two cops shot in ferguson. >> we have to match force with force. >> reporter: the president praising camden's police force and community-based approach. more officers on the streets. violent crime down. the city that was the murder capital of the nation. the white house released a final list of recommendations for police. everything from body cameras to sharing more data with the public about police work. the goal -- to try to restore trust. lester? >> ron allen, thank you. turning overseas where isis has overrun the city of ramadi, a city with a lot of meaning to a lot of american families. not only the capital

of anbar province but where one of three american casualties occurred during the iraq war. now after all that sacrifice by american men and women, ramadi, less than 70 miles from baghdad is now in the hands of the enemy. nbc's bill neely has our report. >> reporter: the retreat from ramadi was fast and humiliating. iraqi troops in dozens of armored vehicle s in a race for their lives. forcing them out, isis fighters who shot this propaganda video showing a city abandoned by the army. isis gunmen controlling the hospital in the city's center. iraqi troops fought for just two days leaving behind american-supplied weapons and tanks. it's a setback for the u.s. a decade ago, nbc news was in ramadi where hundreds of american troops gave their lives to hold the city. today, ramadi is held by the world's biggest terror group. it will be tough to retake.

>> it is possible to have the kind of attack we have seen in ramadi. i am confident in the days ahead that will be reversed. >> reporter: u.s. air strikes have pounded isis positions around ramadi for weeks. it didn't work. air power has its limits. >> the fall of ramadi -- i mean it's huge. >> reporter: critics like senator john mccain are calling for u.s. boots on the ground which the obama administration has so far ruled out. both the u.s. and iraq will rely on shiite militias to retake the sunni city of ramadi. they helped regain tikrit last month but they are armed and backed by iran. its influence is growing. the u.s. is uneasy. iraqi officials say isis or dash, in arabic will be beaten. >> no one here believes dash is going to survive in iraq or for much longer. >> reporter: isis is now pushing toward the capital, baghdad. with u.s. war planes

and iraqi troops struggling to defeat it. nbc news, london. a tragic moment in hawaii. a marine was killed when an osprey aircraft came in for a tough landing during a training exercise yesterday. 21 others had to be taken to the hospital. this happened the same day six other marines who lost their lives were identified after they went down aboard a chopper while on a relief mission in nepal. a lot of people are talking about the incredible claims made by a computer expert who says he successfully hacked into an airplane's controls from his seat in the cabin of the plane. so many wondering if it's even possible and if it is, who else could be trying it? nbc's kerry sanders is getting answers. >> reporter: chris roberts claims he hacked into a commercial airlines cockpit flight controls. >> it is definitely

possible to manipulate the electronics through the in-flight entertainment system and satellite communications to get to the avionics of an airplane. >> reporter: in an affidavit roberts said he hacked into the flight management systems and in one case caused one of the engines to climb resulting in lateral or sideways movement. >> i don't believe it. i consider it to be garbage. >> reporter: today, two government sources close to the investigation tell nbc news initial data analysis shows no proof of roberts' claim. a federal report says that doesn't mean a hack is simply fantasy. the gao just issued a report. and the experts they spoke to said any cockpit that's linked to the outside world should be considered vulnerable and, in their words, open to malicious actors. >> the way we connect the systems using internet protocols, they are going to be more vulnerable. >> reporter: but not on board the aircraft

in which he flew. roberts was on boeing 737s and 757s. experts say today don't have are the advanced wildfire system and therefore cannot be hacked. on the airbus a-320 the fly-by wire system is closed. despite no proof of claims, one of the airlines on which roberts was a passenger -- united -- banned him from their flights forever. kerry sanders, nbc news, miami. the relentless rain in the country's mid section took a devastating turn for a louisiana family when flash floods swept away a car driven by a grandmother taking her grandkids to school. one of the children was later found dead. in texas, the national guard had to use a helicopter to rescue those stranded by floodwaters. there is a lot more to tell you about this monday night. new twists in a baffling murder mystery. a family killed in their multi-million dollar home. a person of interest caught on camera. tonight we are going

to tell you about the strange activity in the neighborhood observed in the days before the murders. later, when you can't find the right words to say to someone you love, one woman says she has just the message and it's catching on.

we are back with new twists in a shocking murder mystery in washington. a family found dead inside their burning mansion as authorities release surveillance video of a person of interest caught on camera. and we are hearing for the first time about strange messages in the hours and days

before the murders. we get the latest from our national correspondent peter alexander. >> reporter: tonight after this multi-million dollar home was found burning in one of washington, d.c.'s most exclusive neighborhoods the mystery is growing. who killed savo savopoulos, his wife amy, their son and a housekeeper. all four found murdered inside. >> they were a very lovely family. very nice family. >> reporter: for the first time we are hearing from a second housekeeper who asked not to be seen on camera speaking to our washington station wrc. she says she received a call from mr. savopoulos last wednesday, the night before the fire, telling her not to come the work the next day. >> he said, i hope you can get this message. my wife is sick. my son is sick and vera offered to stay overnight but her phone is dead. >> reporter: mrs. savopoulos followed up with a text thursday morning.

police suspect the attack may have started as early as wednesday. neighbors reported unusual activity around the family home before the murders including an aggressive door-to-door salesman and a possible prowler. there were no signs of forced entry and investigators are looking for a person of interest seen in this surveillance video. authorities suspect that person of interest was driving the family porsche, later found torched, 15 miles away. >> it's going to be a black porsche convertible. it's going to be behind the church. >> reporter: the savopouloses have two teenaged daughters believed to be at boarding school. on mother's day, days before the attack abigail reportedly posted this moving message to her mom on facebook. thank you for the past 19 years and i look forward to the many more to come, she wrote. i love you so much. a murder mystery haunting the nation's capital. peter alexander, nbc news, washington. when we come back,

a legendary daredevil's final dive. what went wrong in the dark of night in yosemite?

he was a legend in his own time, a man who thrived on finding his limits and pushing past them. over the weekend extreme athlete dean potter and a friend took on a challenge they would not walk away from. jacob rascone has more on potter, who died as he lived -- on the edge. >> reporter: in a sport where one misstep could be your last, dean potter was undaunted, climbing without safety ropes, high lining without a harness and waiting for the last moment to deploy his parachute. >> i'm doing the thing i find beautiful, pushing myself to the

limit of what i feel is possible. >> reporter: potter dropped out of college becoming one of thor world's best known daredevils, even flying with his dog whisper. over the weekend potter and his friend leaped at yosemite national park wearing wing suits and didn't survive. officials are investigating what went wrong. basejumping is illegal at yosemite. around the world some 200 basejumpers is have died since 1980 including sean leery who died in a similar wing suit incident in utah. climbing greats paid tribute to potter including kevin jorgensen who climbed el capitan saying, sad day for the climbing tribe. we lost a legend. i was inspired by how dean relentlessly pursued his passions. until the end almost super human. jacob rascone, nbc news, los angeles. >> on a different note, a few twitter users got an unusual notification today -- you're being followed by the president of the united states. after six years, president obama has his own personal twitter handle --

@potus. his first tweet read, hello twitter. it's barack. really! six years and they are finally giving me my own account. up next, what to do when the traditional get well card isn't going to cutt it for what you want to say.

finally tonight sometimes it's too hard to put our feelings into words. a lot of us let greeting cards do it for us. there are times when the usual sentiments can't capture what we need to say. here's nbc's anne thompson. >> reporter: as a greeting card designer and writer, emily mcdowell knows words matter. her line, a quirky honest twist on get well cards. >> the best seller is let me be the first to punch the next person who tells you everything happens for a reason. >> reporter: what's the chord you have struck? >> i think it is reflecting people's reality in a way that they have never seen before in pop culture. >> reporter: sentiments that come from mcdowell's own experience. >> i had cancer myself when i was 24. i had hodgkin's lymphoma. >> reporter: she

underwent nine months of chemo and radiation. unable to cope some of her friends disappeared and well meaning people said cringe worthy things. >> my uncle's girlfriend had that, ending the story with "she passed away." >> reporter: now the experiences are reflected in the card. i'm sorry i haven't been in touch. i didn't know what to say. in remission, mcdowell put her cancer experience away until her best friend amy died of the disease. she quit her ad agency job to eventually write cards. what began with a valentine two years later is now a los angeles based business with cards and gifts in 1500 stores and growing. >> we are swamped which is fantastic. >> yeah. >> reporter: what's been the most emotional part for you? >> reading stories. i found myself in tears as you -- >> beautifully described your experience, the motivation behind the line. when i read emily's cards i thought this is what we need. we need an opportunity to start the conversation. >> reporter: finding

funny, honest words to acknowledge the pain of disease and loss. anne thompson, nbc news, los angeles. >> and that will do it for us on this monday night. i'm lester holt. for all of us at nbc news, thank you for watching and good night. breaking news happening on the peninsula. a mountain lion on the loose near mateo. less than 15 minutes ago, a gunshot rang out and you can see here police running down the street of a san mateo neighborhood. good evening, thanks for joining us. i'm janelle wang. >> and i'm raj mathai. it's been an active 90 minutes. not often do we have an intense search like this. a big cat has been spotted

multiple times today near downtown san mateo. within the past 15 minutes we heard that gunfire. this is all happening in a populated area right off el camino and 9th avenue just a few blocks from downtown. michelle roberts has been on the scene for hours. michelle what's the status right now? >> reporter: right now we are waiting for an update from police. at this point they're very busy. about 20 minutes ago, we saw a handful of officers running down the street. just a few moments later we heard one shot fired. but at this point we don't know if they actually shot the animal or if it was a miss because right now police are still going door-to-door checking backyards. that's what they have been doing for the last hour or so. this all started at about 4:30 this morning. somebody called 911 because they saw the mountain lion behind their apartment complex near the pool area. police came out and couldn't find anything. again this afternoon, same thing.