A suspect in the attack in Dallas that killed five police officers and wounded seven others, including one civilian, said that he was targeting whites before he was killed by an explosive device sent in by law enforcement. But he told police that he was not linked to any protest movement.

Three other suspects were in custody Friday morning, but officials did not give details about them.

Suspect in Dallas Shooting Unconnected to Black Lives Matter Micah Xavier Johnson
Micah Xavier Johnson, 25

Police identified the individual as Micah Xavier Johnson, 25. He is a veteran and has no criminal record, nor any connections to extremist groups.  Johnson was a private first class from the Dallas suburb of Mesquite with a specialty in carpentry and masonry. He served in the Army Reserve for six years starting in 2009 and did one tour in Afghanistan from November 2013 to July 2014, the military said.

Officers cornered him in a parking garage shortly after the shooting, CBS Dallas reported. He reportedly had no criminal history or ties to any terrorist group. At a Friday morning press conference, Dallas Police Chief David Brown said Johnson was “upset about Black Lives Matter,” the recent police shootings in Louisiana and Minnesota, and that he wanted to kill Whites, especially White officers. He said that the man told hostage negotiators that he was acting alone and was not associated with Black Lives Matter or any other similar group.

The shootings took place Thursday night at what began as a peaceful protest in response to the police involved shooting of two Black men within a 24 hour period. Four of the deceased officers were Dallas police officers and one was with Dallas Area Rapid Transit, according to officials.

The unidentified suspect who was killed threatened police, saying that more police would be hurt and saying that bombs had been planted in the area. An explosives sweep in the vicinity turned up no bombs, according to the Dallas Morning News. “We’re hurting, our profession is hurting,” Brown said at a Friday morning news conference. “There are no words to describe the atrocity that occurred to our city. All I know is that this must stop, this divisiveness between our police and our citizens.”

WFAA in Dallas reported that shots were fired around 9:50 p.m. EDT as demonstrators marched through the city’s downtown area.

A photo of a person of interest was circulated by Dallas police, but that man, Mark Hughes turned himself in. Police later determined that he was not connected to the shooting and he was released from custody.

It was the deadliest day for police since Sept. 11, 2001, when 72 police officers lost their lives when the original World Trade Center in New York was attacked by terrorists.

President Obama addressed the incident while traveling in Poland called the shootings a “vicious, calculated, despicable attack on law enforcement,” vowing that the perpetrators would be brought to justice.

“We are horrified over these events and we stand united with the people and the police department in Dallas,” he said.

The names of the Dallas police officers who were killed have not been released, but DART identified its fallen officer as 43-year-old Brent Thompson, a seven-year veteran. DART police Chief J.D. Spiller told WFAA that he had recently married a fellow officer.

Demonstrations have risen in several cities around the country in response to the police shooting deaths of Alton Sterling in Baton Rouge, La., on Tuesday and Philando Castile in Falcon Heights, Minn.

Witnesses at the Dallas demonstration say that it was a peaceful march with officers and citizens walking together, even taking selfies when the shots were fired from a parking garage near the protest.