police under siege. caught in a sniper's crosshairs as a peaceful protest turns into panic. five officers dead, seven wounded. the deadliest day for law enforcement since 9/11. new details on the lone gunman. >> he wanted to kill white people, especially white officers. >> the tense standoff and the high-tech takedown. plus -- >> [ bleep ]! >> america, black and blue, after three days of bloodshed. tonight, thousands take to the streets in atlanta as the men whose names became hash tags after dying at the hands of police prompt the call for unity. >> nobody should have to be taken away from their family. >> can we ever bridge this painful divide? >> this must stop. >> tonight, a special edition of

"nightline." "ambush in dallas."

this is a special edition of "nightline," "ambush in dallas." >> good evening. thank you for joining us. it's been called the deadliest day for law enforcement in america since 9/11. a lone gunman here in dallas driven by racial hatred opening fire on a peaceful protest against police brutality.

12 officers shot, five murdered. tonight the growing fear and anger on both sides as a nation on edge demands answers. [ gunshots ] >> reporter: dallas. shell shocked and grieving after five police officers were targeted and killed about i a sniper last night. a city under siege. >> black lives matter! >> reporter: just over 24 hours ago, residents here in a rainbow of races and religions peacefully protesting the two recent deadly police shootings of black men in louisiana and minnesota. under the protective eye of the dallas police department -- >> whether you're white, whether you're black, latino, at some point we all need to come together. >> reporter: some officers posing for pictures with protesters in a sign of solidarity. but then, just before 9:00 p.m. -- >> watch out! >> reporter: gunshots. >> assist officers, shot fired,

saying the suspect has a rifle. >> reporter: targeting police officers. >> code 3, officer down. shots fired, officer down. >> reporter: protesters run for their lives. taking cover where they can. >> i ended up getting shot at. >> i ran back. and i was screaming, run, run, run, active shooter, active shooter. >> reporter: police can't pinpoint the exact location of the sniper. >> he went that way! >> we got a guy with a long rifle, we don't know where the hell he's at. >> reporter: as officers move protesters out of harm's way, bullets continue to rain down. >> we can't even protest a shooting right now. oh my good. >> reporter: clarissa pyles was at the protest when the shooting started. >> pop, pop, pop, pop, pop! we are all on the ground right now. >> reporter: she live streams it on facebook. >> i see a police officer come and he's yelling at us, get down on the ground, get down on the ground, get down on the ground! at that point i just immediately dropped down to the ground. >> reporter: she was one of the many who captured the violence with their cell phones as it

unfolded. it seemed like a coordinated team of snipers. >> these suspects were positioning themselves in a way to try and triangulate on these officers from two different perches in garages in the downtown area. >> reporter: from a nearby rooftop, this video. a witness sees a shooter pacing back and forth with a rifle. moments later a police officer approaches. the gunman lunges. the officer killed in a hafl bullets. >> he's down! >> reporter: as people flee into the night, blocks away from the protest route on the second floor of a parking lot year elcentro college, a gunman cornered by police. >> officers on floor 2, taking fire with suspects shooting at police. >> reporter: a standoff lasting hours. the talks break down. police take the desperate measure for the first time in law enforcement history, a robot armed with a bomb is sent in and kills the suspect. >> we saw no other option but to use our bomb robot and place a

device on its extension. >> they made the tactical decision, a bit unusual, that was the way obviously to end it without anybody else getting hurt. >> reporter: five police officers were killed that night. 43-year-old brent thompson, a member of the transit police, married two weeks, was the first to die. dallas police officer patrick zamarripa, veteran of three tours in iraq, leaves behind two young children. his family is heartbroken. >> ever since he was a little boy, he talked about becoming a police officer. and that was his dream. and he fulfilled his dream. by going into the navy and then becoming dallas p.d. >> reporter: another victim, officer michael krol, served with the dallas p.d. for nine years. >> great guy. he was a dedicated policeman. like he had committed himself real early in his life to being a policeman. and he went down to dallas. because he wanted to live down there. he just loved it down there. >> reporter: sergeant mike

smith, age 55, was also killed. and the fifth officer, senior corporal loren aarons. at baylor medical center, police held vigil for their fallen colleagues and the one still injured. seven more men and women, along with two civilians, one of them transit officer misty mcbride, shot in the arm and the abdomen. she's expected to recover. her daughter expressing the family's relief. >> i'm just happy that she will be okay, that they can live into tomorrow, and i'm glad that she's alive. >> reporter: shetamia taylor, recovering in the hospital, was at the rally with her sons, her sister says shot trying to shield her boys from gunfire. >> she said as she started to run she caught a bullet in the back of her right leg. she immediately jumped on top of one of her boys, the 15-year-old. she jumped on top to cover him on the ground as she pushed him in between two cars and the curb. >> reporter: the sniper has been

identified as 25-year-old micah xavier johnson. his words and his actions reveal a deep racial hatred. >> he said he was upset about the recent police shootings. the suspect said he was upset at white people. the suspect stated he wanted to kill white people. especially white officers. >> reporter: johnson's facebook page content reveals some of that rage against police. he liked a page which said, kill everything blue that moves. law enforcement sources tell abc news johnson was armed for his shooting spree with an assault rifle and two handguns. he'd served in the army reserve in 2009 until 2015 and did a tour in afghanistan. today police searched johnson's home in mesquite, texas, where detectives found bomb-making materials, ballistic vests, rifles, ammunition, and a personal journal of combat tactics. maybe neighbors in his quiet suburb of in dallas were stunned the shooter was living amoney

them. >> this guy lived around the corner from me. was willing to take people's lives he didn't even know. it's scary. >> reporter: another neighbor told us he saw johnson doing what looked like tactical army training in his backyard, crawling on the ground with a rifle. micah johnson's sister took to her facebook page to defend her brother writing, the news will say what they think but those of us who knew him know this wasn't like him. during the chaos of the attack, authorities initially feared there could be multiple shooters. but tonight law enforcement sources tell abc news they believe johnson was the lone gunman. across the nation, the ambush set police departments on edge. in new york, washington, d.c., chicago, and other large cities. police officers will now double up when they go on patrol. it appears police are being targeted elsewhere. in georgia, missouri, and tennessee. authorities detail three incidents where police were fired on. all are expected to survive. >> i'd ask all americans to say

a prayer for these officers and their families. keep them in their -- in your thoughts. and as a nation, let's remember to express our profound gratitude to our men and women in blue, not just today, but every day. >> reporter: president obama is cutting his trip to europe short and will visit dallas next week. the emotions are raw in the city. a prayer vigil earlier today -- >> we need citizens to show officers that they appreciate their sacrifice. but we are determined to not let this person steal this democracy from us. >> reporter: the mayor, mike rawlings, calling for solidarity in the face of tragedy. >> we ask, what could we do to build the bonds of peace and reconciliation? today, we find ourselves here again.

and this time the terror has hit us right here in downtown dallas just a few blocks away. we are thankful for our lives. others lost them last night. we are thankful for our families. other families lost that last night. we are thankful for our city, yes. we are thankful for each other. >> reporter: outside the police department, a makeshift memorial. >> these guys take care of us. >> we need to have their backs as well. we need to support and protect them as well. >> reporter: for those police officers who lost their lives. and next, two lives cut brutally short by police. those shootings triggered the ambush in dallas. my "nightline" coanchor juju chang looks at the charges of police brutality fueling so much anger. but i didn't really think

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heavily armed sniper in dallas targeted white officers. as payback, according to authorities, igniting new racial tension in a country already divided by race. as we close out this bloody week, anger first sparked by graphic videos of fatal shootings of black men by police turning to heartbreak and calls for peace between black and blue. >> get on the ground! >> reporter: nine gunshots. fired 1,200 miles apart. >> oh my god, please don't tell me he's dead. >> reporter: two lives ended. but not erased. >> jesus, no! >> reporter: the last breaths of

alton sterling and philando castille caught on smartphones, viral, heart-wrenching videos. the moments they became the 559th and 563rd persons killed by police this year. and while the numbers are compelling, what lingers are these heart-rending images seared into our psyche as they join the ranks of michael brown, eric gardner, tamir rice. a club no one wants to belong to. last year alone, roughly 1,000 men and women were killed by police. and while it's true that in overall numbers the majority of those killed were white, black americans are disproportionately the victims. they're just 6% of the population, yet 40% of the unarmed men shot and killed by cops. >> hands up, don't shoot! >> reporter: the fight for black lives versus blue lives tragically intersecting. as an otherwise peaceful protest is obliterated by the assassination of five police officers in dallas. by a man who didn't heed martin

luther king jr.'s words -- darkness cannot drive out darkness, only light can do that. investigators will try to shed light on what happened in that car. and at that gas station. those stinging videos combed through frame by frame in elusive pursuit of justice. >> it could have been me versus him. >> you're always thinking, i could be next. you're always thinking that. >> reporter: black men posting to facebook and twitter detailing instructions of what to do if theirs is the next name to make the news after a police-involved shooting. >> i don't know very many african-americans or latinos in america who have peace, because we're constantly living under a state of siege. >> reporter: over 5 million weighing in online around the world, giving new breadth to a type of tragedy that's become almost despairingly routine. >> i don't think we're becoming desensitized to it, i think we're becoming more and more fed up to it. >> reporter: jay-z calling out police shootings in a raw, newly

released song "spiritual." ♪ i am not poison i am not boy john ♪ ♪ just a boy from the hood that got my hands in the air in despair don't shoot ♪ >> reporter: saying, "we should be further along, we are not." dallas representative mark veasy as he talked about his role both as a lawmaker and a black father. >> he's a cute fifth grader. but i worry about him. when he gets older, when he gets into high school, what if he's out with friends and he smarts off the wrong way? and i just don't want anything to happen to him just because i want that for my son does not mean that i don't support the police 100%. >> reporter: outside an lapd graduation, rapper snoop dogg and the game leading a peaceful rally. their intent, to build a better relationship between cops and communities of color. >> hunt us not today.

hunt you not today. >> reporter: in atlanta this dramatic scene as thousands spill onto the streets in peaceful protest. but some of the most powerful words come from here on the ground. the places directly touched by tragedy. in baton rouge a community standing hand in hand singing "amazing grace." ♪ amazing grace >> reporter: in minneapolis, a new cry for justice. back in dallas, mourning the loss of five men gunned down protecting those protesters serving their city. mayor mike rawlings charging forward in a city shaken. >> that we as a city, as a state, as a nation, are struggling with racial issues. they continue to divide us. yes, it's that word race. and we've got to attack it head-on. >> reporter: it's a unity born of tragedy. a cause championed with renewed fervor. perhaps this is small solace to

those who loved alton sterling and philando castille. >> no justice no peace! >> reporter: to alton sterling's family, he was the one they could always count on to be generous to a fault. >> he was a gentle guy, a big boy but gentle as a lamb. he gave when he couldn't afford to give. he fed when he couldn't afford to feed. >> he was a very outspoken person, a people's person. >> reporter: to the 500 children at philando's school, he was the school lunch manager who took the time to learn each one of their names and food allergies. >> he never gave his mama no kind of trouble. that's why she can't understand why, you know. he got killed like that. >> he was a family member to many, many people but he was the only family that me and my daughter really had here in minnesota. and they took that away from me. they took him away from me. now who's going to protect us? it hurts me, what's going on in dallas.

because nobody should have to be taken away from their family. >> reporter: so many lives, black and blue, taken far too soon. up next, we'll go back to my "nightline" coanchor byron pitt in dallas. along with the urgent calls for peace, prayers for healing for those those grieving tonight. new, two in one heartburn relief. the antacid goes to work in seconds... and the acid reducer lasts up to 12 hours in one chewable tablet. try new duo fusion. from the makers of zantac. ...one hair color wants to to help you keep on being you.. nice'n easy. natural-looking color... ...that even in sunlight, doesn't look like hair color... it just looks like you. nice'n easy: color as real as you are. and i quit smoking with chantix. i have smoked for 30 years and by taking chantix, i was able to quit in 3 months

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finally tonight, i talked with reverend michael waltrip, a minister involved in the demonstration last night. sunday he says he's going to preach, you can't defeat hate with hate, only with love. >> when i hear the claims for black lives matter, it's saying, we want to matter on the plane of humanity. we want the same rights. we want the same recognition of all. for some people who have been fighting this fight for so long with strained voices, their tone shifts and they begin to demand justice. and it doesn't sound as palatable to us as to dr. king. but it moves up from a great sense of deep pain. >> as someone by your own account follows in dr. king's legacy, what do you make of this

moment when police officers were killed, people were gathering to demonstrate the loss of black lives, now these law enforcement officers? >> there are two ways to consider it. one is that in dr. king's very first book "stride toward freedom," he talked about police brutality. that lets us know that it's an issue that has been with us for a long time. but we can also take courage in dr. king's words that hate cannot drive out hate, only love can do that. and if we follow the principles of love and of community-building, i believe we'll all be the better for it. ♪ >> it was the late nelson mandela who once told me, "good and evil are constantly at war, so good men and women must choose." thank you for watching abc news. for more on this story, tune in to "good morning america" tomorrow. as always, we're online on our "nightline" facebook page and at