Authorities in San Diego are investigating whether the man who shot an off-duty police officer is connected to two other robberies that happened hours apart Monday.

Police say the officer was shot outside a bank in the suburb of Escondido by a man wearing a baseball cap that said, "POLICE" on it, KFMB-TV reported.

The shot reportedly grazed the unidentified officer's head but did not puncture his skull; he was able to stumble into the bank where witnesses helped him before authorities arrived on the scene. He has been hospitalized for observation.

The shooting occurred three hours after a holdup outside another bank in Mission Valley, about an hour south of the shooting location. The victim in that incident said his wallet and other possessions were taken at gunpoint by a man dressed like a security guard who identified himself as a police officer.

An hour after the shooting, witnesses at a shopping mall said a man and a woman wearing vests with the word "POLICE" on them set a vehicle on fire and carjacked another person, using the victim's car to escape from the area.

KFMB's report on the three incidents, aired Monday, can be seen below.