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" apparently acted alone in a sniper attack that killed five police officers at a protest in Dallas 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 garage, ending an hours-long standoff.
A search of Johnson's home in the nearby suburb of Mesquite found "bomb-making materials, ballistic vests, rifles, ammunition and a personal journal of combat tactics," Dallas police said in a report on Friday. Police said Johnson had no previous criminal history.
On Thursday night, 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 two black men this week in Minnesota and Louisiana. Police officers patrolling the Dallas demonstration at the time believed they were under attack by several gunmen.
By late afternoon on Friday, however, investigators had concluded that Johnson, armed with a rifle, was the lone gunman.
"At this time, there appears to have been one gunman, with no known links to or inspiration from any international terrorist organization," U.S. Homeland Security Secretary Jeh Johnson told reporters in New York.
At a news conference in Dallas, the city's mayor, Michael Rawlings, said the shooting "came from one building at different levels from this suspect."
Three other people were detained by police, but authorities have not publicly linked them to the shootings. Still, officials said they were looking for evidence of any possible co-conspirators.
The ambush marked the highest death toll for U.S. police in the line duty from a single event since the Sept. 11, 2001, attacks.
GUNMAN ANGRY ABOUT POLICE KILLINGS
The attack was certain to complicate rising tensions between minority communities and law enforcement following a string of high-profile killings of unarmed black men at the hands of police across the country over the past two years, giving rise to the Black Lives Matter protest movement.
The latest violence, which occurred as one such rally was coming to a quiet end, was especially devastating for the people of Dallas, a city that struggled for decades to heal from the scars left by the 1963 assassination of President John F. Kennedy, blocks away in Dealey Plaza.
Dallas Police Chief David Brown called Thursday's incident "a well-planned, well-thought-out, evil tragedy." He added, "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 African-American.
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, Johnson 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 salute.
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 man carrying an assault-style weapon and large amounts of ammunition.
The video shows the gunman 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.
The Rev. 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."
President Barack Obama, in Poland for a NATO summit, called the Dallas shootings "a vicious, calculated and despicable attack on law enforcement." Obama, who has been 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."
As Dallas reeled from a night of carnage, there was a flurry of other shootings directed at police across the country.
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. A 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 Hillary Clinton and Donald Trump, the presumptive Democratic and Republican U.S. presidential nominees, respectively, canceled their campaign events for Friday following the attack.
(Reporting by Brendan O'Brien in Milwaukee, Eric M. Johnson in Seattle, Jon Herskovitz in Austin, Texas, Letitia Stein in Tampa, Florida, Laila Kearney and Gina Cherelus in New York, Fiona Ortiz in Chicago and Mark Hosenball in London; Writing by Jon Herskovitz and Steve Gorman; Editing by Will Dunham and Leslie Adler)