Since 9 11. Were live from dallas with all the latest on the investigation. Nightly news begins right now. Announcer tragedy in dallas, this is nbc nightly news with lester holt reporting from dallas. Police say the shots that turned the streets behind me in the killing zone, taking the lives of five Police Officers and wounding 11 others and a civilian. Tonight the nation shares dallass anxiety and shock at how a Police Protest against the death of a black man. As marchers rang in fear from the shots, police took cover and desperately tried to neutralize the attacker. Tonight we have learned that the sniper is an army war veteran. Reporter the ambush was well planned, well thought out and evil, police say. Hundreds of protesters caught in the cross fire, while officers were targeted in cold blood. I didnt see anybody else get shot, it was just the cops. Reporter tonight the gunman is identified as 24yearold Micah Johnson. He was wearing body armor and he was laughing and singing during his hours long standoff with police. The suspect said he was upset at white people. The suspect stated he wanted to kill white people, especially white officers. Reporter the march began just after 7 00, following this weeks High Profile Police shootings in louisiana and minnesota. Starting near main street, the first hour mostly peaceful. The Police Wearing not wearing riot gear. But just before 9 00, cops dodging for cover. Shots fired, officer down. Reporter panic in downtown dallas. We were trying to run and grab kids and help their mothers to get somewhere safe because we didnt want anybody getting hurt. Reporter the man who organized the protest. About 25 feet, and thats when i heard it. Pow, pow, pow. And i saw what i think was two Police Officers drop. Reporter one by one, the horrifying death toll rises as Dallas Police reported on social media that two Police Officers were shot from elevated positions during the rally. I heard the first shot, but like him, i didnt realize it was a shot. The crowd was screaming and pandemonium. Reporter at some point, the sniper was hit by gun fire. After 11 00, s. W. A. T. Team cornering johnson, with a standoff stretching well past midnight, until officers had no other option but to send in a row got to detonate a bomb near the suspect. Police say at least three people were detained and questioned, but late today, dallass mayor says he believes johnson was the lone gunman. Police saying i cant believe whats going on. Reporter tonight, this man is safe. I thought for a second, i wasnt going to be able to get out of there. Reporter police say johnson used a handgun and a rifle. Right now there are no other suspects or other persons in custody. But this investigation is ongoing, many streets hire in dallas shut down and they will remain that way until next wednesday. And we heard marchers wanting to get in and get their belongings and their cars, but all of this is shut down. Were learning a lot more about the Police Officers killed in the horrific ambush here. More on the five fallen officers, and a mother who reportedly shielded her sons from the gun fire. Reporter a poignant memorial outside the Dallas Police department is just starting to take shape as more about the five fallen officers take shape. Thats one of the tough things. I mean, the loss of a great officer, the loss of a husband, after being married for only two weeks. Reporter the four other victims all served the Dallas Police department, including officer patrick, who survived two tours in iraq, he too was survived by his wife and two children. A Police Officer, this doesnt get any better than this, this is pure goodness. I mean hes just a guy who wants to serve and protect during the day and then go watch a ball game with his family at night. Reporter another victim, officer michael krol became a cop so he could help people. Wanted to make things right, was really committed. That was probably the most frustrating thing for him, he could. Solve it all. Reporter several more were injured including misty mcbride who was shot in the arm and abdomen. Im just glad that shes alive. Reporter two citizens were also hit by gun fire,. The tragedy is relationship between police and the community is improving, since 2010, Excessive Force complaints have dropped by 83 . Now theyre mourning the loss of five officers who protected their city to the end. We dont feel much support most days. Lets not make today most days. Please, we need your support. Reporter of the seven officers who were injured in that attack, Officials Say most have been treated and released from the hospital. Lester, this is the deadliest day for u. S. Law enforcement since 9 11. All right, joe friar, thank you, joe. New details are emerging about the lone system, a 25yearold black army veteran who lived outside of dallas. Police searched his house today carrying out bags of evidence. Jacob rascon is also at the home and has more for us. Reporter they spent nearly three hours inside the gunmans home. Dallas Police Detectives and atf agents emerging with large bags of evidence. Inside bomb making materials, ballistic vests, rifles ammunition and a journal of combat tactics. A neighbor who didnt want to be identified says Micah Johnson didnt hide his arsenal. How did you know he had a lot of guns . He told me. I know he was part of the army, a sergeant or something. I know hes military or something. Reporter the gunman worked for mentally challenged kids and adults. He and his mother lived here for many years, neighbors say. Military records confirm johnson was an Army Reservist for six years, serving two tours in afghanistan, he was the recipient of various medals and ribbons. Neighbors say they would see johnson practicing on obstacle courses in his backyard. This man who came out of the gunmans home didnt want to answer question questio questions. What was your reaction when you heard about this . Shootings of black men drove him to go on this rampage. Tonight the governor of texas says that although investigators believe that johnson was a lone gunman, they want to be confident there werent any coconspirators or anyone especially who knew about the attacks, that investigation is ongoing. Lester . With the country on edge about the dallas shootings, other cities are taking extra precautions for the safety of their officers tonight. The reporter tonight a nation united in pain, but divided too, as people gather around the country, rallying against violence. While the violence continues. This morning in georgia, a Police Officer ambushed and shot responding to a 911 call. And in baldwin, missouri, an officer shot during a traffic stop. Yesterday afternoon in tennessee, a gunman upset about violence against africanamericans killed one woman and shot three others including a Police Officer. The new york tabloids highlighting the countrys division, madness, civil war. In washington, congressman john lewis pleaded for unity. We must learn to live together as brothers and sisters, if not, we will perish has fools. Reporter then what words could not accomplish, a moment of silence in congress. Today Police Officers are on heightened alert. Being told to double up before going out in boston, seattle and chicago. The delicate balance of protecting the community and protecting themselves is highlighted in this shooting. Even as bullets were raining down, the officers went to proteblg the protesters. Reporter in los angeles, rapper snoop dawg. John legend weighing in on social media, being against cops killing is not equal to being for killing cops. Unity yes, but division too. Instagram is packed with images. Is his life worth more than mine . His life matters, his life matters. A woman in washington summing up the feelings of many. I dont want black men shot at traffic stops, i dont want cops shot by snipers, i dont want kids shot at school, i dont want any of this. A nation in mourning. President obama today responded to the massacre here during his trip to poland for the nato summit. Donald trump and Hillary Clinton cancelled Campaign Stops today. Reporter president obama, an ocean away, once again responding to a crisis back home. I would ask all americans to say a prayer for these officers and their families. Reporter and last night, before dallas, his first comments about the two africanamerican men killed by police this week. This is not just a black issue. Its not just an hispanic issue, this is an american issue. Reporter not breaking away from his trip yet, although he still may, even as the nation is gripped by the horror of dallas, dallas now haunting president ial politics at least today. Hillary clintons planned first rally with Vice President joe biden in scranton, casse casse cancelled. Clinton did keep a commitment tonight to an African Methodist Episcopal Church conference. I want white people to understand how africanamericans feel every day. I want people to put themselves in the shoes of Police Officers and their families. Reporter at the capitol, a moment of silence, an emotional speaker ryan. I know that to be a cops wife or a cops husband is to prepare for the worst. But who could have fathomed such horror as this. Theres been too many begguns, too much violence. Reporter Police Politicians and pastors also respecting how to respond to a heart sick nation. Still ahead tonight, how police used a robot to take out the suspect, a method apparently never before used on u. S. 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Back now from dallas, where police ended the deadly siege on the city last night by using a robot with a bomb to kill the ambush suspect. His attacks straight from the wars in iraq and afghanistan. It appears to be the First Time Police have ever used a robot bomb on u. S. Soil. Reporter with five officers dead, 14 people injured and unable to get a clean shot, Dallas Police turned to battlefield tacticses to take out the gunman, using a robot to deliver and then detonate an explosion. Reporter in recent years, s. W. A. T. Teams have come to rely on robots, sent in with cameras to locate a gunman, locate suspicious bags and even detonating explosives. Reporter i think it was very unusual, i think it was very innovative and they made the right decision. Reporter but delivering a bomb was not the original intent. Robots have been around for decades, but the batless in iraq and afghanistan have required a far more robust robot. The american bomb squad as a small fleet of remote lly operated robots. Equipped with cameras, microphones, cameras, claws, you name it. We have different kinds of class that we can pick up, we can pick up a small breaker of unstable chemicals or pick up a big box or open a car door. Reporter the question for s. W. A. T. Teams nations wide what dallas marks the start of a change in police tactics. Were back in a moment with a father and son who attended last nights protest im phil mickelson, pro golfer. My Psoriatic Arthritis caused joint pain. Just like my moderate to severe rheumatoid arthritis. And i was worried about joint damage. My doctor said joint pain from ra. Can be a sign of existing joint damage. That could only get worse. He prescribed enbrel to help relieve pain and help stop further damage. Enbrel may lower your ability to fight infections. 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Castile, i wanted to be a part of a movement, i wanted to teach my son that we have rights in this country and that we can express our frustration in a positive way. What did you think when you heart the shots . Why . I thought, we just made a grave mistake, we set the africanamerican race back, we set the human race back many years by allowing this to happen. Are you afraid now at all . Im not afraid, im cautious but not afraid. I think people who are afraid act irration irrationally. Whats the message that police can take from this . Love their family, make sure their family knows they love them every day before they leave the house. The message i dont want them to take is to be afraid of africanamerican men. I dont want them to think that we dont want them to do their jobs as long as theyre doing their jobs within the confines of the law. And you dont want your son is to be afraid of police . I dont want him to be afraid of police at all. To go from peace, to go from joy, from being inspired to horror that unfolded the way it did. Life is fragile. When we come back, ill have some final thoughts on the violence in week and where we are as a nati in a world held back by compromise, businesses need the agility to do one thing another. Only at t has the network, people, and partners to help companies be. Local global. Open secure. Because no one knows like at t. And my results ended up beinge african, european and asian. It was great because it confirmed what i knew in my gut with a little surprise. Ancestry helped give me a sense of identity. Folks out there whose diabetic nerve pain. Shoots and burns its way into your day, i hear you. To everyone with this pain that makes ordinary tasks extraordinarily painful, i hear you. Make sure your doctor hears you too i hear you because i was there when my dad suffered with diabetic nerve pain. If you have diabetes and burning, shooting pain in your feet or hands, dont suffer in silence step on up and ask your doctor about diabetic nerve pain. Tell em cedric sent you. Finally tonight, we have just witnessed two awful days that have sickened us, bewilders us and even scared us. Back to back cell phone videos of controversial shootings of black men by police that have left people questioning the values of their very lives. And late yesterday the horror here in dallas, the hateful attack by a young black man against Police Officers as they enforced one of our basic rights, the right to have a peaceful protest. The nation takes a step back to find meanings in all of this. One thing is for sure, everyone who stepped on the street last night had the expectation and certainly the right to safely return back to their families when the march was over. Those whose lives were suddenly and violently taken in those two days have left their marks to reconcile our differences, to reconcile race. Maybe were not there yet, but maybe we can agree that too many tears from fallen to stop trying. Another half hour of nightly news is just ahead. Announcer this is nbc nightly news with lester holt. During a protest over the killings of black men by police. Late today, authorities said they believe this was the act of a lone gunman, 25yearold micah xavier johnson, a black man who lived just outside of dallas. Police said he told them he was out to kill white officers. They negotiated for hours, when those negotiations failed, police sen i