The gangbanging teen who gunned down an innocent dad on a Brooklyn bus wasn’t the only person on board who was packing heat, Police Commissioner Bill Bratton said Monday.

Six cameras on the B15 captured the Clinton Hill shooting on Thursday in every angle.

“I spent a long half hour looking at that murder over and over,” said Bratton.

The top cop said at least two riders on the bus had guns, but there could be more.

“There was quite a few of them engaged in what was basically going to be a gun battle on that bus,” he said. “Fortunately, the others were not able to get their guns out before they fled.”

Kahton Anderson, 14, allegedly opened fire at a rival and hit Angel Rojas, 41, in the head.

Rojas, a hard-working father of two, was going home to visit his family in between his two jobs.

Bratton said the NYPD’s challenge is to deal with the many young people who carry guns.