Snipers ambushed police officers in downtown Dallas Thursday night, as a peaceful protest turned into chaos.
Five officers were killed. Seven other officers and two civilians were wounded.
Police said the snipers were on a mission to kill as many officers as they could in a coordinated attack. Three suspects are in custody. A fourth suspect was killed after a standoff with police. Police Chief David Brown said negotiations broke down and authorities "saw no other option" but to to use a bomb robot to carry an explosive over to the suspect's location and detonate it.
"Other options would have exposed our officers to grave danger. The suspect is deceased as a result of detonating the bomb," Brown said during a press conference Friday morning.
During the negotiations, however, Brown said the suspect told them he was upset over the recent police shootings of black victims and wanted to kill white people, especially white police officers.
The evening began with a protest march in solidarity with victims in this week's police killings of two men in Louisiana and Minnesota, reports CBS News correspondent Manny Bojorquez. But just before 9 o'clock, officers with the Dallas Police Department and Dallas Area Rapid Transit (DART) were targeted by an enemy they couldn't see.
The unprecedented assault unleashed dozens of rounds on downtown Dallas. People marching at the rally stopped walking to run for their lives.
The view from above shows how hundreds of people scattered.
"I was screaming, 'Run, run, run! Active shooter, active shooter!"' the Rev. Dr. Jeff Hood, a rally organizer, said.
As the attack went on, several uniformed officers were down, motionless, on the pavement outside. Officers ran to the aid of their wounded colleagues even as the gunfire continued.
One of the suspects, a man with a rifle, fired shots while hiding behind a pillar.
"We got a guy with a long rifle but we don't know where the hell he's at," an officer could be heard saying over the police scanner.
Brown believes this was a coordinated strike on his police force.
"Working together with rifles triangulated at elevated positions in different positions where the march ended up going. ... Why would you know to post up there?" Brown said.
Two suspects were arrested in a traffic stop after a brief chase. One suspect was a woman who was caught in a community college parking garage.
Four of the officers who were killed were with the Dallas Police Department. One was a DART officer.
"It is a heartbreaking morning. ... To say that these police officers put their lives on the line every day is no hyperbole, it's a reality," Dallas Mayor Mike Rawlings said.
The shooter who was involved in the standoff with police claimed bombs were planted throughout the area. Dallas police, joined by ATF personnel, used bomb sniffing dogs to search the downtown area, and found no explosives, a law enforcement source told CBS News senior investigative producer Pat Milton.
Police officials CBS News spoke to around the country described an unease for the safety of police on patrol, reports CBS News correspondent Kris Van Cleave.
Miami police told us they will be gathering Friday to create contingency plans for their city, while the Las Vegas Police Department said its officers will be working in pairs until further notice.
This is not the first time in recent memory that officers have come under fire during a protest. In Ferguson, Missouri in March of last year, two cops were shot during a demonstration outside of police headquarters.
A former law enforcement source told CBS News adding additional cops to patrols is common in situations like this. But despite heightened concern for their safety, it is also in the back of officers' minds to be extra careful with their actions because they themselves are more in the spotlight than ever.