An Army veteran “upset about Black Lives Matter” and “recent police shootings” who opened fire Thursday night in Dallas in an attack on police officers has been identified as Micah Xavier Johnson, the Los Angeles Times and CBS News report.

Five police officers were killed and seven were wounded, officials said. Two civilians were also wounded in the shootings. Johnson, 25, was killed when a police robot detonated a bomb near him following a standoff that lasted several hours, Police Chief David Brown said Friday at a press conference.

“The suspect said he was upset with white people and wanted to kill white people, especially white officers,” Brown said.

It is not clear if there were any other gunmen, or whether other people taken into custody by police were involved in the shooting. Police initially said two snipers positioned themselves in triangulated locations to fire on officers from elevated positions.