DALLAS -- Dallas police say multiple pieces of evidence were seized from the Mesquite home of shooting suspect Micah Xavier Johnson, an Army veteran they say shot 14 people, killing five police officers, Thursday night.
Inside his home in Mesquite, ATF and police investigators found bomb-making materials, rifles, ammunition, ballistic vets, as well as "a personal journal of combat tactics," DPD said Friday.
Photos: Authorities search ambush suspect's Mesquite home
Police say they believe Johnson, 25, opened fire from an elevated height after a peaceful protest ended in Downtown Dallas. It was being called a "justice rally" and was part of a nationwide protest following officer-involved shootings in Louisiana and Minnesota.
Johnson was eventually cornered by DPD officers during a 45-minute standoff, Dallas Police Chief David Brown said during a Friday press conference. He said during negotiations, Johnson told police he wanted to "kill white people, especially white officers."
He was eventually killed after negotiations didn't work and an exchange of gunfire ensued. Officers used an explosive device to kill Johnson, Chief Brown said.
The suspect was wearing armor and had multiple rounds of ammunition on him. The chief said Johnson acted alone and wasn't affiliated with any groups.
PHOTOS: Officers killed in downtown shooting
News 8 has learned that he served in the U.S. Army Reserve for six years, and was stationed at the Seagoville Reserve Base in North Texas at one time.
He spent eight months in Afghanistan between 2013 and 2014, the Army said. USA Today reported Johnson was a private first class with a specialty in carpentry and masonry.
Our sister station in Houston, KHOU, has confirmed that Johnson was connected to the New Black Panther Party three years ago for a few months before he was kicked out of the group.
Community activist Quanell X says Johnson was a hot head with violent ideas. He says he advised the leadership to distance themselves from Johnson.
A former co-worker of Johnson's had similar things to say.
“I was really cursing this guy and hoping that they got him. And I wake up and I see not only did I know this guy, but he got blown up!” said Nick, who asked us not to share his last name.
Nick said he worked with Johnson at a Richardson Jimmy John’s in 2012. “It was pretty well known in the restaurant that he had a short temper,” he said. “That he was a hothead.”
According to Nick, Johnson was written up on the job for that attitude, and it led to his firing.
Neighbors didn’t know Johnson well, but they knew recent police shootings deeply upset him.
"He said how tragic it is and said that Police are trying to wipe out the black race," said Israel Cooper, who said he’d play pickup basketball with Johnson.
Few knew he’d seek revenge in a shower of bullets.
The ambush in Dallas is being called the deadliest day in the nation for law enforcement officials since the Sept. 11, 2001 terrorist attacks.
USA Today contributed to this report.