Spokesman Frank Fisher said the suspect walked into Washington Federal bank, at 3761 Highway 528, around 2:30 p.m.
Once inside, he threatened a teller and demanded money before being given an undisclosed amount and leaving, he said. The suspect ran north, a couple blocks, to a vacant house on Cielo Vista del Sur before leaving in a green SUV, possibly a Land Rover.
The suspect is described as a white male, in his 40s, with a heavy build. He wore a black ski cap, black jacket with a white Under Armour logo, black pants, and a dark bandana over his face.
Fisher said the FBI may pay a reward of up to $1,000 for information leading to the arrest and conviction of the suspect.