© NBC DFWPolice swarm downtown Dallas Thursday July 7, after gunshots rang out following a protest and rally held over police shootings in other parts of the U.S.
The snipers fired from an elevated positions on police officers minutes before 9 p.m. CT, according to Dallas Police Chief David Brown. He described the shootings as "ambush style."
"We believe that these suspects were positioning themselves in a way to triangulate on these officers from two different perches in garages in the downtown area, and planned to injure and kill as many law enforcement officers as they could," Brown said at a news conference — noting that some were shot in the back.
Police were in a standoff with one suspect in the second floor of a parking garage at around 12:30 a.m. and were exchanging gunfire with him, Brown said. Another suspect, a woman, was taken into custody near the garage, and two people seen leaving the area in a Mercedes were stopped and were being questioned.
The suspect in the standoff with police "has told our negotiators that the end is coming, and he is going to hurt and kill more of us, meaning law enforcement, and that there are bombs all over the place in this garage and downtown," Brown said.
There may be others out there. "We still don't have a complete comfort level that we have all the suspects," Brown said, warning that a search in downtown could last through morning. Police were in contact with the FBI and federal Bureau of Alcohol, Tobacco, Firearms and Explosives, Brown said.
Brown said investigators are working under the assumption that all suspects were all working together. They have not been cooperative, he said.
"We just are not getting the cooperation we'd like to know that answer of why, the motivation, who they are."
Police initially said three officers were killed. A fourth officer who had been in surgery later died, Brown said. Three of the four slain officers were Dallas police officers, and the fourth was a Dallas Area Rapid Transit officer, he said. A civilian was also wounded, authorities said.
Around 800 people were at the demonstration, and around 100 police officers were assigned to the event and the surrounding area, Dallas Mayor Mike Rawlings said. The shooting occurred after the demonstration ended and as a march was taking place.
"At 8:58, our worst nightmare happened," Rawlings said. "It is a heartbreaking moment for the city of Dallas, Rawlings said.
A person at the protest said they were "making our second lap" when gunfire erupted.
"We heard shots, we smelled gunpowder, and that's when everything got really intense and surreal," the witness told MSNBC. "We just started to run and grab kids," he said.
The demonstration was in reaction to the police shootings of Alton Sterling in Baton Rouge Tuesday and Philando Castile Wednesday in a St. Paul suburb.
Texas Gov. Greg Abbott directed the state Department of Public Safety to offer any assistance needed. "In times like this we must remember — and emphasize — the importance of uniting as Americans," Abbott said in a statement.
The demonstration in Dallas was one of several held in cities across the county Thursday, most of them peacefully.
In Saint Paul, Minnesota, a crowd estimated to be more than a thousand strong gathered outside a school where one of those men killed, Philando Castile, worked as a kitchen supervisor.
In Baton Rouge, Louisiana mourners gathered in a "second line" parade for Alton Sterling, who was killed by police on Tuesday in an incident that was recorded on video by a bystander. The Department of Justice Civil Rights Division is investigating that shooting.
"It can be any brother or sister out here. This ain't just started; they've been killing us," Chermicka Brown, a friend of Sterling's who joined protesters outside the store where he was shot, told NBC affiliate WVLA in Baton Rouge.
Hundreds of people gathered in New York City's Union Square before groups marched through parts of Manhattan. Police said they made arrests in Times Square, but a number was not immediately available.
"It's the definition of insanity," Michael Houston, a 20-year-old student in New York, told The Associated Press. "How can we expect anything to be different when nothing changes?"
Both shootings were recorded on video. "It disrupts and it crumbles all of the progress that's been made; it's unfortunate," Andre T. Mitchell, the founder of a Brooklyn-based group that works toward improving relations between the community and the police, told NBC New York. "It just sets us back."
"It's supposed to be innocent until proven guilty. But the way I see it, it's murder first and ask questions later," another protester in New York, Lawrence Amsterdam, 35, told the AP.
There were also demonstrations in Washington, D.C., Atlanta and Seattle. Protests were scheduled in Oakland, California, Thursday.
Minnesota Gov. Mark Dayton said at a news conference earlier Thursday that he was "appalled" by the shooting death of Castile, and said that had he been white he likely wouldn't have been shot.
Anyone else see this as all to convenient for the old sympathy wars.
The cops needed their own to perish or they wouldn't have a leg to stand on.