Sebastian Sobczak was walking down the street near the World Trade Center when he heard yelling and saw a mangled yellow school bus. With camera in hand, he went to take stock of what was happening and spotted several children inside the bus.

“They’re stuck in there!” the bus driver yelled.

“Oh my God!” Sobczak said. “Can you call 911? Oh my God!”

Video that Sobczak provided to CNN shows the hectic moments after a man drove a rented truck into cyclists and pedestrians Tuesday on a bike path in Lower Manhattan, killing eight people in the deadliest terrorist attack in New York since 9/11.

Sayfullo Saipov, the suspect in the attack, then slammed into the school bus, authorities said. The collision stopped the suspect, and he exited the truck brandishing imitation weapons before police shot him and took him into custody.

The suspect’s white truck can be seen in the background of Sobczak’s video, but the focus is on students stuck in the caved-in bus. Two students can be seen through a window, and another appears lodged underneath a hunk of mangled metal.

Police quickly arrived on the scene, and later in the video footage, first responders work to rescue a trapped child.

The crash injured two children and two adults, New York Police Commissioner James P. O’Neill said Tuesday.

And Sobczak said he’s unlikely to forget what he saw.

“The horror of hearing that bus driver and those screaming kids will haunt me,” he said.