By Ernest Scheyder and Marice Richter
DALLAS (Reuters) - A black U.S. military veteran of the Afghan war who said he wanted to "kill white people" opened fire in a sniper attack in which five police officers were slain at a protest decrying police shootings of black men, officials said on Friday.
Seven other police officers and two civilians were wounded in the ambush in downtown Dallas on Thursday night, officials said. Police killed the gunman, identified by authorities as 25-year-old Micah Johnson, with a bomb-carrying robot after cornering him in a parking lot, ending an hours-long standoff.
The sound of gunfire sent a panicked crowd of hundreds of protesters screaming and running for their lives near the end of an otherwise peaceful march to protest police killings of black men this week in Minnesota and Louisiana. Police officers patrolling the demonstration at the time believed they were under attack by several gunmen.
U.S. Homeland Security Secretary Jeh Johnson told reporters in New York that "at this time, there appears to have been one gunman, with no known links to or inspiration from any international terrorist organization."
Dallas police said in a report they searched Johnson's home in the Dallas suburb of Mesquite and found "bomb making materials, ballistic vests, rifles, ammunition and a personal journal of combat tactics." Police said he had no previous criminal history.
Three other people were detained by police, but authorities have not publicly linked them to the shootings.
The Louisiana and Minnesota shootings, both the subject of federal investigations, were the latest in a series of similar incidents that have triggered protests over police use of force against black suspects and racial disparities in the American criminal justice system.
The march was affiliated with Black Lives Matter, a decentralized movement that arose after the series of police killings to protest the treatment of black people by U.S. law enforcement.
Dallas Police Chief David Brown called the incident "a well-planned, well-thought-out, evil tragedy," adding, "We are determined to not let this person steal this democracy from us."
During lengthy negotiations with police, the gunman told police he was angry about the Louisiana and Minnesota killings, Brown told reporters.
"The suspect said he was upset at white people. The suspect stated that he wanted to kill white people, especially white officers," said Brown, who is black.
Some details began to emerge about Johnson. He posted a rant against white people on a black nationalist Facebook group called Black Panther Party Mississippi last Saturday, denouncing the lynching and brutalizing of black people.
"Why do so many whites (not all) enjoy killing and participating in the death of innocent beings," Johnson wrote in his Facebook post above a graphic video of people participating in a whale-killing, comparing it to the treatment of black people in the United States.
In what appeared to be his own Facebook page, he was portrayed as a black nationalist, with images of Black Power and the red, black and green flag sometimes known as the Black Liberation flag. His profile photo showed him with his clenched fist in the air in the familiar Black Power gesture.
The U.S. Army said Johnson, 25, had served as a private first class in the Army Reserve and was deployed to Afghanistan from November 2013 to July 2014. It said Johnson served from March 2009 to April 2015 and was a carpentry and masonry specialist with the 420th Engineering Brigade based in Texas.
'HEARTACHE AND DEVASTATION'
Details on how the shootings unfolded remained unclear. Video of the attack taken by a witness shows a gunman carrying an assault-style weapon and large amounts of ammunition.
The video shows a man with a rifle crouching at ground level and charging at and then shooting another person who appeared to be wearing a uniform. That person then collapsed to the ground.
Reuters could not immediately confirm the authenticity of the video.
Reverend Jeff Hood, an organizer of Thursday night's protest, said he had been chatting with some of the police officers on the street when gunfire erupted.
"I saw what I believe were two police officers that went down. I didn't know what to do," Hood told reporters on Friday. "If we continue to turn to violence, we are going to continue to see heartache and devastation."
It was the deadliest day for U.S. police since the Sept. 11, 2001, attacks.
President Barack Obama, in Poland for a NATO summit, called the Dallas shootings "a vicious, calculated and despicable attack on law enforcement." Obama, stymied by the Republican-led Congress in his bid for new gun control laws, added, "We also know when people are armed with powerful weapons unfortunately it makes attacks like these more deadly."
Three of the slain officers were identified on Friday. One was Brent Thompson, 43, who joined the Dallas Area Rapid Transit police department in 2009, according to police. Another was Patricio Zamarripa, 32, an U.S. Navy veteran, according to his family. Also killed was Michael Krol, 40, according to the Wayne County Sheriff's Office in Michigan, where he used to work.
A man in Tennessee opened fire on a highway, killing a woman and grazing a police officer with a bullet on Thursday, because he was troubled by incidents involving black people and law enforcement, authorities said on Friday. Police officers also were ambushed and wounded in shootings in Missouri and Georgia on Friday.
Largely peaceful protests unfolded around the United States after the police shooting of Philando Castile, a 32-year-old black man, on Wednesday during a traffic stop near St. Paul, Minnesota. The day earlier, police in Baton Rouge, Louisiana, shot dead Alton Sterling, 37, while responding to a call alleging he had threatened someone with a gun.
Both major U.S. presidential contenders canceled their campaign events for Friday following the attack.
(This version of the story has been corrected to read "the gunman told police" instead of "the gunman told reporters" in paragraph 10)
(Reporting by Brendan O'Brien in Milwaukee, Eric M. Johnson in Seattle, Jon Herskovitz in Austin, Texas, Letitia Stein in Tampa, Florida and Laila Kearney and Gina Cherelus in New York, Fiona Ortiz in Chicago and Mark Hosenball in London; Writing by Scott Malone and Jon Herskovitz; Editing by Will Dunham)