Investigators said the man robbed a US Bank branch inside a Vons grocery store in Torrey Hills on Friday.
He is also suspected in two other bank robberies in Santee and La Jolla.
The suspect is described as a thin white male in his 70s with gray hair.
During Friday's robbery he was wearing a blue baseball cap and eyeglasses.
Anyone with information is asked to call Crime Stoppers at (888)580-8477.