Police are trying to hunt down a gunman who shot and killed another man on an MTA bus in the Bronx Monday, sending other passengers fleeing the vehicle in terror.

Surveillance video shows the chaos that followed the middle-of-the-afternoon shooting. People are seen running away from the BX36, near the corner of White Plains Road and East Tremont Avenue.

At least one of them is pushing a stroller.

People in the area said they’ve been on heightened alert recently — and the shooting is an example why.

“I feel like we have to watch out, like I can’t even take my little baby out to just pick him up from school,” said Joanna Rios of Van Nest.

According to the NYPD, the gunman and the dead man were both passengers. They had a dispute, and the victim was shot in the chest. It’s not clear if the two knew each other prior to the bus encounter.

The nature of the dispute wasn’t immediately clear, but reports indicate it was noise-related.

The victim was identified as 41-year-old Jonathan Pettigrew of the Bronx.