Jason Young witnessed a police officer killed at "point blank." Carlos Harris heard the sound of guns firing: "tap, tap pause." Cortney Washington saw cops "bending" over and getting shot.
The three were among the witnesses who experienced the chaos and horror after police officers were ambushed at the end of a demonstration in the heart of Dallas against recent police shootings in Minnesota and Louisiana.
Five officers were killed and seven injured in the attack Thursday night, the deadliest day for law enforcement since Sept. 11, 2001. Two civilians were also injured.
The shooting began about 8:45 p.m. while hundreds of people were gathered to protest the week's fatal police shootings in Baton Rouge, Louisiana, and suburban St. Paul, Minnesota.
Young was watching the demonstration at a bus stop while on his way home from work at the Kay Bailey Hutchison Convention Center when he saw people running after gunshots were heard. He said an officer was hiding behind a pillar and a second person run up behind him, wearing body armor and gear.
Young said he thought it was just another police officer until the man shot the officer at "point blank" range.
"I'm still in shock. I mean, I've never seen anything like that before in my life. Never would have expected that," Young said. "We all just hit the ground, just laid on the ground for a few minutes."
After shooting the officer, the gunman ran around the north side of El Centro community college where he shot out some windows and went inside, Young said.
The shooter, identified by police as Micah Xavier Johnson, was killed after authorities cornered him in a garage at the college. After several hours of negotiations police exchanged gunfire with Johnson, then killed him by detonating a bomb on the end of a robot, Police Chief David Brown said Friday morning.
On Friday afternoon, multiple senior U.S. law enforcement officials said the investigation so far has led them to believe that Johnson was the lone gunman. Police initially said they believed there were two shooters. After the standoff ended, Dallas' police chief gave no more details about a possible second shooter.
Dallas Rally Organizer on Attack: It Was 'Mayhem'
The law enforcement officials told NBC News that they believe Johnson acted alone and investigators have not found ties between Johnson and any extremist groups so far.
Video from the scene showed protesters marching along a downtown street about half a mile from City Hall when shots erupted and the crowd scattered, seeking cover. Officers crouched beside vehicles, armored SWAT team vehicles arrived and a helicopter hovered overhead.
A witness who didn't give his name told MSNBC that his group was making a second lap of the event when gunfire erupted.
"We heard shots, we smelled gunpowder, and that's when everything got really intense and surreal," the man said. "We just started to run and grab kids."
Devante Odom, 21, told The Dallas Morning News: "Everyone just started running. We lost touch with two of our friends just trying to get out of there."
Harris, who lives downtown, told the newspaper that the shooters "were strategic. It was tap, tap pause. Tap, tap pause," he said.
Renee Sifflet told the paper that she took her three teenage children to the rally "for a positive experience, something they could say they were part of when they're older."
"Then it turned negative," Sifflet said.
The scene was chaotic, with helicopters hovering overhead and officers with automatic rifles on the street corners.
A witness who posted video to Facebook said he saw at least three officers wounded near El Centro College. The video showed police cars swarming the scene and sirens blaring.
Another video appeared to show a gunman at ground level exchanging fire with a police officer who was then felled.
"I saw all the cops were bending over. There had to have been five or six cops, and they were all getting shot down. It was right after the rally, we were walking to the car," said Washington.
Dallas Police Chief Discusses Shootings in Press Conference
"They kept shooting. It was coming — we didn't know where it was coming from. And I didn't see anybody else get shot. It was just the cops. I didn't see nobody else get shot," she added.
The search for the shooters stretched throughout downtown, an area of hotels, restaurants, businesses and some residential apartments. The area is only a few blocks away from Dealey Plaza, where President John F. Kennedy was assassinated in 1963.
Cory Hughes, who helped organize the rally, told NBC 5 the protest was peaceful and as the crowd begun to disperse, they heard gunfire.
"They were shots ringing out from what felt like every direction," Hughes said.
He said the scene turned into "mayhem; we didn't know where to go."
He said he knew it was a serious situation when he saw officers coming from all directions, carrying rifles and tactical gear.