US: Dallas cop shooter Micah Xavier Johnson was Army reservist in Afghanistan

The sniper who shot 12 police officers in the US city of Dallas, killing five and injuring many, during a protest decrying police killings of black men this week, has been identified as a former Army reservist equipped for war.

Micah Xavier Johnson, 25, was wearing body armour and totting an SKS semi-automatic assault rifle and a handgun when he started picking off cops in downtown Dallas late Thursday night during a "Black Lives Matter" protest, law enforcement sources said.

Police on Friday found bomb-making materials, ballistic vests, rifles, ammunition and a journal detailing combat tactics during a search at the home of Johnson, who told negotiators during the "ambush" that he 'wanted to kill white people' as he went on a shooting rampage killing five cops.

In a statement on Friday afternoon, Dallas police confirmed the identity of the gunman and said he was described as a "loner" by some who knew him. Detectives were in the process of analysing the information in the journal, the statement said.

(The attack came during one of several protests across the United States against the killing of two black men by police- Reuters)

Well-trained in using the weapons

Johnson was well-trained in using the weapons of war. He served as a reservist for six years until 2015 and was deployed in Afghanistan between November 2013 and July 2014, authorities said.

He was a carpentry and masonry specialist, with a rank of private first class, and was awarded the Army Achievement Medal. But he didn't have an especially glowing reputation among members of his unit.

"We all knew he was a pervert because he got caught stealing girls panties but murdering cops is a different story," Wells Newsome, a former bunkmate of Johnson's, wrote on Facebook.

"You really never know what someone is capable of until it's too late."

Luis Canto, another fellow reservist, said Johnson had an erratic personality.

"We all knew he was off, man, but no idea he was capable of that," Canto wrote on Facebook.

The cold-blooded cop assassinations carried out by Johnson, who had no criminal record or ties to terror groups, stunned his family members.

"I keep saying it's not true," Johnson's sister Nicole said in a Facebook post. "My eyes hurt from crying. Why him? And why was he downtown."

"The news will say what they think but those that knew him know this wasn't like him," Nicole Johnson added in a separate post. "This is the biggest loss we've had."

(People shout slogans against police as they take part in a protest against the killings of Alton Sterling and Philando Castile during a march in New York July 7, 2016. Credit: Reuters)

Bloodbath

Johnson's rampage turned what had been a non-violent rally into a bloodbath.

Amid the massacre, Johnson told a police negotiator he was targeting white officers because he was angry over the recent spate of cop-involved killings.

"He said he was upset about the recent police shootings," Dallas Police Chief David Brown said. "The suspect said he was upset at white people. The suspect stated he wanted to kill white people, especially white officers," Brown added.

The assault ended when Johnson was killed by a bomb strapped to a police robot.

Support for several groups associated with black nationalism

The cop killer's Facebook profile picture shows him dressed in a 'dashiki' and holding a clenched fist in the air in a black power salute.

He shows support for several groups associated with black nationalism, including the Black Riders Liberation Party and the New Black Panther Party.

Johnson's step-mother Donna Ferrier Johnson, who is white, posted a picture of him on Facebook decked out in fatigues and driving a military vehicle.

Dallas crime scene investigators were inside Johnson's single-family brick home in Mesquite, located about 12 miles outside of Dallas, for several hours yesterday morning.