DALLAS _ Investigators have discovered bomb-making materials, rifles and a "personal journal of combat tactics" in the home of the black former Army reservist who went on a shooting rampage against Dallas police, officials said Friday.
Micah Xavier Johnson, 25, a Dallas-area resident, was a "loner" with no criminal history who "wanted to kill white people" and "especially white officers," police said.
Five Dallas police officers died and nine other people were wounded in the attack, which unfurled Thursday night in the midst of a large protest against recent police shootings of black men in Louisiana and Minnesota.
The injured included seven police officers and two civilians.
Using an unprecedented tactic in American law enforcement _ and apparently adopting technology used by the U.S. military _ Dallas police said they detonated an unmanned "bomb robot" to kill Johnson early Friday after negotiators failed to bring an end to an hours-long standoff in a downtown parking garage.
Before his death, Johnson "bantered" with police negotiators, a federal official said, adding that the suspect did not appear nervous. He indicated he had been preparing for the assault, the official said, and Dallas Mayor Mike Rawlings said the suspect himself chose how it ended.
"This was a man we gave plenty of options to, to give himself up peacefully, and we spent a lot of time talking. He had a choice to come out and we would not harm him, or stay in and we would. He picked the latter," he said.
Officials had initially reported that multiple snipers opened fire on police, but Rawlings said Friday that Johnson was the "lone gunman in this incident."
"This was a mobile shooter that has written manifestos on how to shoot and move. He did that. He did his damage. But we did our damage to him, too," Rawlings said.
Texas Gov. Greg Abbott also said authorities "have no information about any co-conspirators."
But he said police are working hard to "button down every corner" before they rule out the possibility that he had help.
"What we don't know is who, if anybody, may have known what the gunman knew, what he was going to do, may have assisted him in any of his efforts," the governor said.
At one point, the gunman had told officials "the end is coming, and he's going to hurt and kill more of us," Dallas Police Chief David Brown said.
Johnson had no ties to terror groups, a U.S. law enforcement official said, and had relatives in Mesquite, Texas, just east of Dallas.
But on Facebook, Johnson expressed an interest in black separatist groups such as the New Black Panther Party, the Nation of Islam and the Black Riders Liberation Party, according to the Southern Poverty Law Center, which describes the organizations as "hate groups."
In his Facebook profile photo, Johnson wore a purple, yellow and gold dashiki and thrust his fist into the air. His cover photo displayed the red, black and green stripes of the Pan-African flag.
He had joined several groups that made allusions to the Black Panther Party, including a group called the Huey P. Newton Gun Club, named for the black power group's co-founder. The group, which was founded last year to fight police brutality, teaches its members self-defense and conducts what it calls "armed patrols" through neighborhoods where the police have killed black men.
"We'd never seen him and we don't know him," member Erick Khafre said in a telephone interview. "The gun club isn't affiliated with him in any way."
Last week, Johnson shared a video of pilot whales being killed by whalers in the shallow waters off the Faroe Islands. "Look at the joy on their faces," Johnson wrote. "Why do so many whites (not all) enjoy killing and participating in the death of innocent beings?"
He continued: "The church members and regular citizens (offspring of terrorist invaders) who stood around watching, cheering, eating food with their families while watching one of our ancestors be beaten, noose tied around their neck, hung up high for all to see ... then they all stand around and smile while their picture is taken with a hung, burned and brutalized black person."
Johnson's sister on her own Facebook page mourned the loss of her brother and questioned why he had gone to the downtown demonstration.
"I keep saying it's not true ... my eyes hurt from crying," Nicole Johnson wrote in a post she later deleted. Minutes later, she posted again. "The news will say what they think but those that knew him know this wasn't like him," she wrote. "This is the biggest loss we've had."
Outside City Hall on Friday, activists said they did not recognize Johnson or his name, and had never seen him at a protest.
"Never in our wildest dreams would we think our efforts to save lives would take lives," protest organizer Dominique Alexander said.
Military records provided by the Department of Defense say that Johnson served in the U.S. Army Reserve as a carpentry and masonry specialist from March 2009 to April 2015, including a tour in Afghanistan from November 2013 to July 2014 with the 420th Engineer Brigade.
Authorities believe Johnson took frequent target practice, according to a law enforcement official.
U.S. Attorney General Loretta Lynch said federal agencies already are cooperating in the investigation.
"We intend to provide any assistance that we can to investigate the attack and also to help heal a community that has been severely shaken and deeply scarred by an unfathomable tragedy," Lynch said at a news conference in Washington.
"Our hearts are broken by this loss," she said.
President Barack Obama, in Poland for a NATO summit, earlier expressed condolences to the families of the victims in Dallas.
"There has been a vicious, calculated and despicable attack on law enforcement," Obama said. " ... There is no possible justification for these kinds of attacks, or any violence against law enforcement. Justice will be done."
Brown said a hostage negotiator spoke with Johnson at length before he was killed about 2:30 a.m. According to the chief, the gunman said he was upset "with white people" and with recent police shootings. He also said that he was not affiliated with any groups and that he acted alone, Brown said.
"The suspect said we will eventually find the IEDs," Brown said, a reference to explosives. "He wanted to kill officers. And he expressed killing white people, killing white officers, he expressed anger for Black Lives Matter."
"We saw no other option than to use our bomb robot and place a device on its extension to detonate where the suspect was," Brown said, adding that, "other options would have exposed our officers to grave danger."
Brown said reports that the suspect shot himself were incorrect. "The suspect is deceased as a result of detonating the bomb," he said.
Brown said he spoke overnight with the families of the officers who had been shot, adding that most of those who were injured had been released from the hospital. He said three officers listed in critical condition were improving but that they and the department needed the public's support.
Of the dozen officers shot _ 10 men and two women _ eight are Dallas police and four are Dallas Area Rapid Transit, or DART, officers, officials said.
"They know the city is grieving with them," Rawlings said.
Rawlings said that when he met with the wounded officers, he expressed support on behalf of the city and also made them a promise: "We'll get the bad guys."
One of the officers had surgery overnight and was doing well, Rawlings said. He said he spoke with another officer shot in the leg, and another shot in the arm. "The one shot in the leg _ three officers from his squad had died, had gone down around him," Rawlings said. "He felt sad for the other officers, that people don't understand the danger of dealing with a protest. What it can do is put our officers in harm's way."
The shooting broke out late Thursday during what had been a peaceful protest against the recent fatal shootings of black men by police officers in a Minneapolis suburb and in Baton Rouge, La. About 800 people were marching through downtown flanked by about 100 police officers when the gunfire began.
The Rev. Jeff Hood, 32, a Baptist minister based in Dallas, helped organize the protest as a way for people to gather and vent.
"It was a peaceful protest, no question about it. The entire thing was peaceful," said Wood, who was marching alongside a police sergeant at one point.
They were marching in front of several hundred people when Hood heard rapid-fire gunshots: pah, pah, pah-pah-pah.
"Immediately I looked up and saw two police officers that had gone down," he said. "I saw it. I mean, I saw people drop. I knew."
Wood grabbed his own shirt, instinctively, "Because I thought I might have been shot." He had not. He looked up again, and saw the police sergeant take off down the street toward the gunshots. Hood ran the opposite direction, shouting to the crowd, "Run, active shooter!"
Hood had a small cross and held it up above the crowd, he said, guiding them like a shepherd's crook. Many of them kept asking him why the shooting happened. He wondered the same thing.
"The rest of the night I spent ministering people, trying to make some sense of what happened," he said.
Officials identified one of the slain officers as Brent Thompson, 43, who had worked for the DART Police Department since 2009. He was the department's first officer to be killed in the line of duty. Three other DART officers were injured but were expected to recover, officials said.
"As you can imagine, our hearts are broken," the transit district said in a statement. "This is something that touches every part of our organization."
The other officers who were killed were members of the Dallas Police Department, officials said.
Amanda Mann, a 35-year-old Dallas resident, said she drove downtown with friends shortly before 7 p.m. to catch the beginning of the protest in Belo Garden Park, which she had learned about through Facebook. For the first hour it felt familiar, much like previous Black Lives Matter protests she's been to, she said.
"Until 7:45 there were just some speakers, they were positive and proactive, then they said we were going to line up and march," she said.
Mann said that around 8:30 p.m. or 8:45 p.m., as the rally was dying down and she was walking to her car near El Centro College, she heard the first barrage of shots, and then a group of protesters came running toward her, away from the gunfire. For about 40 minutes, she said, police shouted at protesters to move from one block to the next as officers tried to chase down suspects.
Mann said that at one point she lay down with a group on the grassy knoll of Dealey Plaza, a downtown park that is best known as the site of the 1963 assassination of President John F. Kennedy. At another point, she said, she was near the county jail a few blocks away before running across the Commerce Street Bridge over the Trinity River, away from the scene.
"It was like nothing I had seen before," Mann said. "We just kept following what the police told us to do."
