SEPTA Police are investigating a violent, caught on video brawl on a trolley over the weekend.

The attack took place on the transit authority's Route 10 line at 11:23 p.m. Saturday night as it ran westbound toward West Philadelphia, SEPTA officials tell NBC10.

In the video recorded by a passenger and first published by blogger Brian P. Hickey, a group of people punch, stomp and kick a person laying on their back in the trolley's aisle. (The video was posted below, but the owner has since removed it from public view.)

At the same time, another group wails on a person sitting in a seat further up the trolley.

When people begin yelling that police were being called, the group moves toward the center of the vehicle. But fists keep flying.

SEPTA officials said the brawl lasted for some time before the trolley was stopped at 49th and Lancaster Streets.

