Police have confirmed the gunman who killed five officers in an ambush in Dallas was a 25-year-old named Micah Johnson, an Army veteran and reported "loner" from Texas with no criminal history.
On his Facebook page, Micah appears with his right arm raised in the tight fist reminiscent of the black power movement of decades ago in America.
Johnson, who is black, wears a colorful, loose-fitting African style tunic against the backdrop of the red, black and green Pan-African flag, which became popular during the black liberation drive of the 1960s in the United States.
"During the search of the suspect's home, detectives found bomb-making materials, ballistic vests, rifles, ammunition, and a personal journal of combat tactics," it said in a statement, adding that detectives were analysing the information contained in the journal. Information provided through the course of the investigation indicates that the suspect was an Army veteran and others have identified him as a loner," said a Dallas Police statement.
"The suspect has no criminal history," the police statement added.
It noted that Johnson's Facebook page referred to Richard Griffin of the
Dallas police say the gunman staged a furious ambush-style attack Thursday night in Dallas at a rally held to protest this week's fatal shooting of two black men by police in other states.
Five police were shot dead and seven were wounded, as were two civilians.
The shooter, who told police he acted alone, was killed by a bomb carried by a police robot device after an hours-long standoff with the authorities.
While negotiating with police, he said he was acting in support of the Black Lives Matter movement and that he wanted to kill white people, particularly police officers.
At some point Friday, Johnson's Facebook page was taken down from the social media giant. But screen shots of it show several photos posted by Johnson and other information about him.
Another photo is of a black and white drawing of a fist and the words black power in capital letters.
A resident of the Dallas area, Johnson served six years as a private in the army reserve and was in Afghanistan from November 2013 to July 2014, the Army said. It said he was a carpentry and masonry specialist.
On his Facebook page, his "likes" include a number of organizations listed as hate groups by the Southern Poverty Law Center, which studies such movements in the United States.
They include the New Black Panther Party and the Nation of Islam, both known for expressing virulently anti-Semitic and anti-white views, the SPLC said in a statement.
Another of his "likes" is a group called the African American Defense League.
One of that organisation's leaders is a self-described psychotherapist, poet and black nationalist named Mauricelm-Lei Millere.
After this week's police shooting death of a black man named Alton Sterling in Baton Rouge, Louisiana, Millere called for violent retaliation by blacks.
It noted that Johnson's Facebook page referred to Richard Griffin of the rap group Public Enemy, aka Professor Griff, who the department said "embraces a radical form of Afrocentrism."
The White House said earlier that investigators have "ruled out" any link to domestic or international terrorism in the Dallas shooting.
At a news conference in New York, US Homeland Security Secretary Jeh Johnson said the gunman appeared to have acted alone.
The White House said on Friday that investigators had "ruled out" any links to domestic or international terrorism in the shooting of five police officers in Dallas during a protest against police killings of black Americans.
"It is my understanding that investigators have now publicly ruled out the possibility that the individual who carried out this terrible act of violence had any sort of connections to terrorist organisations, either in the United States or around the world," White House spokesman Josh Earnest told reporters in Warsaw.
"I don't think there's a link to any sort of terrorist conspiracy," added Earnest, giving a briefing at a NATO summit in the Polish capital attended by President Barack Obama.
The spokesman added that there were no immediate plans for Obama to alter his travel arrangements to return to the United States.
"It's something we'll follow closely and if it's something that merits a change in plan we'll let you know," Earnest added.
Obama earlier on Friday called the shootings a "vicious, despicable and calculated" attack.
IMAGE: Micah's Facebook page 'likes' include a number of organisations listed as hate groups by the Southern Poverty Law Center. Photograph: Micah Johnson/Facebook