Slain Dallas suspect said he wasn't part of group, wanted to kill white cops - police chief

The suspect was identified as Micah Xavier Johnson, 25, police said, according to reports.

READ MORE: Snipers shoot 12 officers, killing 5, during demonstrations in Dallas

The snipers were “working together with rifles, triangulating at elevated positions in different points in the downtown area where the march ended up going,” Brown said.

“We are leaving every motive on the table on why this happened and how this happened."

MORE: Fourth #Dallas shooting suspect was killed by bomb robot, police chief says https://t.co/4DsbZ0ixwD pic.twitter.com/UwGp9a4gS1

— CBS News (@CBSNews) July 8, 2016

“He was upset about Black Lives Matter,” Brown said at news conference. “He was upset about” the shootings in Louisiana and Minnesota. “He wanted to kill white people, especially white officers.”

Follow RT's LIVE UPDATES on the story

The suspect, who was later killed during the standoff, told negotiators that he wasn’t affiliated with any group and was acting alone, according to Brown.

Chief: Suspect seemed lucid during negotiations. He expressed killing white people/white officers. He has anger towards #BlackLivesMatter.

— CBSDFW (@CBSDFW) July 8, 2016

#UPDATE: Police Chief: Suspect in Dallas shootings said he wanted to kill white officers: https://t.co/jeSCcij99s pic.twitter.com/zf7kK6eyZk

— CBS 13 News (@WGME) July 8, 2016

"We're hurting, our profession is hurting... we are heartbroken,” he added.

The violence started on Thursday night during a peaceful protest in Dallas over the fatal shootings of Alton Sterling in Baton Rouge, Louisiana, and Philando Castile in St. Paul, Minnesota. At least four attackers, holed up in a downtown garage, used sniper rifles against police officers.

The incident then spread to the streets, where major corporations, restaurants and courthouses have premises. Police believe the attack was coordinated.

Two officers injured in the shooting are in surgery while three remain in a critical condition, according to KTRK news. The condition of the sixth injured officer is unknown. One of the injured officers is mother to a 10-year-old girl.