MILWAUKEE -- Milwaukee authorities are looking for a man who they said attacked a city bus driver.

Investigators with the Milwaukee County Sheriff's Office released a surveillance video on Thursday in the hopes of catching the culprit, WISN-TV reported.

The sheriff's department said the man attacked the driver as soon as he got onto the bus.

The driver drove about two blocks before the attacker turned the steering wheel and stepped on the accelerator, deputies said.

The bus eventually crashed into a tree. That's when the attacker got off the bus and ran away, investigators said.

The driver suffered minor injuries.