A man carjacked a woman on the northwest side Friday night, but police say that was just the beginning of his crimes.

The man jumped in the woman's car in the 4300 block of Dean Pannill, hit her with a gun and stole her car, her purse and a cell phone.

Police say a motorcycle officer later stopped the man for a traffic violation on Marbach, not realizing the car was stolen.

They say the cop was getting off his motorcycle when the man threw the car into reverse and slammed into the bike injuring the officer.

Police say the man then drove away.

Police later found the car crashed into a median at Military and Westbriar, but the suspect was gone.

Investigators say if they find him he could face aggravated robbery, and aggravated assault on a police officer charges.

Police say the carjack victim suffered a cut to the head, and the officer had minor injuries to his legs.