Bomb-making materials, ballistic vests, rifles, ammunition and a personal journal of combat tactics were found in the Dallas shooting suspect’s house, officials said Friday. Five police officers were killed, seven additional officers and two civilians injured when suspect Micah Xavier Johnson opened fire during a Black Lives Matter protest in Dallas on Thursday. Authorities believe he was working alone.

Johnson who was an Afghanistan veteran drawn to Black Power symbology told officials during negotiations that “he wanted to kill officers, and he expressed killing white people. He expressed killing white officers. He expressed anger for Black Lives Matter,” Dallas Police Chief David Brown said.

“This was a mobile shooter that has written manifestos on how to shoot and move. He did that. He did his damage. But we did our damage to him, as well,” Dallas Mayor Mike Rawlings reportedly said.

Micah Johnson Micah Xavier Johnson, a U.S. Army reservist who shot dead five Dallas police officers in July 2016, is seen in an undated photo from his Facebook account. Photo: MICAH X. JOHNSON VIA FACEBOOK VIA REUTERS

The standoff between Dallas police and Johnson ended early Friday morning when the police detonated a bomb robot killing the 25-year-old. During the negotiations, Johnson told officers, “The end is coming, and he’s going to hurt and kill more of us,” Brown said adding that this was a “well-planned, well-thought-out, evil tragedy.”

 “This was a man we gave plenty of options to, to give himself up peacefully, and we spent a lot of time talking,” Rawlings said, “He had a choice to come out and we would not harm him, or stay in and we would. He picked the latter.”

Johnson lived with his mother in Mesquite, an eastern suburb of Dallas when he left active duty. Authorities reportedly said that Johnson was in the U.S. Army Reserve from March 2009 to April 2015. He was honorably separated from the reserve. He served in Afghanistan from November 2013 to July 2014. He even won awards for his service, including the National Defense Service Medal and Army Service Ribbon.

Law enforcement officials said that one of the weapons used by Johnson in the Dallas attack was an AK-47-style rifle.