On Thursday, July 7, 2016, people rallied in Dallas, Texas, to protest the fatal shootings of Alton Sterling, a Baton Rouge man whose death on Tuesday at the hands of police was captured on cellphone video, and Philando Castile, a black motorist who was shot at close range by a Minnesota cop and seen bleeding to death in a graphic video shot by his girlfriend that went viral Thursday.

People rally in Dallas, Texas, on Thursday, July 7, 2016 to protest the deaths of Alton Sterling and Philando Castile.

During the protest a sniper opened fire on police officers. Twelve officers were shot in what Police Chief David Brown called an "ambush style" attack.

Pictured: A sniper is seen firing from behind a column in downtown Dallas.

Witness Michael Bautista posted video of a barrage of gunfire, and the police response, near the intersection of Main and Lamar Streets in downtown Dallas.

Bystanders stand near police barricades following the sniper shootings in Dallas on July 7, 2016.

A Dallas police helicopter flies near the scene where 12 Dallas police officers were shot.

Police Chief David Brown blamed "snipers" and said early Friday that three suspects were in custody. (It was later reported that police believe the others arrested were not related to the shooting.)

At a Friday press conference Chief Brown reported one suspect, who was later killed, told negotiators that he was "upset" about the recent police shootings of black men: "The suspect said he was upset at white people. The suspect said he wanted to kill white people - especially white officers."

Mayor Mike Rawlings said the suspect who made that statement was slain by a police explosive in a downtown parking garage where he had exchanged gunfire with authorities. He was identified as 25-year-old Micah Xavier Johnson.

Micah Xavier Johnson, right, the shooting suspect who died in a confrontation with Dallas Police, is seen in a photo obtained by CBS News.

Emergency responders administer CPR to an unknown patient on a stretcher as law enforcement officials stand nearby at the emergency receiving area of Baylor University Medical Center, early Friday, July 8, 2016, in Dallas.

A Dallas police vehicle that has a red fluid stain beneath the door is hauled away from the Baylor University Medical Center emergency room, Friday, July 8, 2016, in Dallas.

Police check a car early Friday, July 8, 2016, in Dallas, after snipers opened fire on police officers Thursday night. Five officers were killed and seven wounded, police said.

Dallas police move to detain a driver after several police officers were shot in downtown Dallas, July 7, 2016.

Dallas police check a car after detaining a driver in downtown Dallas on Thursday, July 7, 2016.

Dallas police stand watch near the scene where five Dallas officers were fatally shot on July 7, 2016. Seven other officers and two civilians were wounded.

Protesters yell after police officers arrest a bystander following the shooting at a protest in Dallas on July 7, 2016.

Police attempt to calm the crowd as someone is arrested following the sniper shootings in Dallas on July 7, 2016.

A police officer tries to calm protesters following the sniper shootings in Dallas on July 7, 2016.

Bystanders stand near police barricades following the sniper shootings in Dallas on July 7, 2016.

A clerk looks at broken windows shot out at a store in downtown Dallas, Friday, July 8, 2016.

Police tape marks off the area where a shooting took place in downtown Dallas, Friday, July 8, 2016. The night before, a sniper opened fire on police officers in the heart of Dallas during protests over two recent fatal police shootings of black men. Five Dallas officers were killed and seven wounded.

Brent Thompson, of Dallas Area Rapid Transit, was one of five officers killed in the shooting in Dallas.

An undated family photo of Patrick Zamarripa, a U.S. Navy veteran and one of five Dallas Police Officers killed in an ambush on July 7, 2016.

An undated photo shows Dallas Police Senior Cpl. Lorne Ahrens, one of the officers killed in an ambush July 7, 2016 in Dallas.

An undated photo shows Dallas Police Sgt. Michael Smith, one of the officers killed in an ambush July 7, 2016 in Dallas.

A handout photo shows Michael Krol, one of the officers killed in an ambush July 7, 2016 in Dallas.