According to Livermore Police Spokeswoman Traci Rebiejo, police received a call at 4:26 p.m. on Oct. 29 from the owner of the Shell Gas Station on 809 E Stanley Blvd.
"He said he had been robbed at gunpoint and that a quantity of cash was taken," Rebiejo said. "The suspect fled south through the parking lot, then out of sight."
The suspect was described by the gas station owner as a Black male adult, stocky and wearing all black with a black cloth covering his face, police said.
Police arrived a few minutes after the call and set up a perimeter. One individual matching the description was stopped but then released after police determined they weren't involved.
No vehicles were seen and no injuries reported, Rebiejo said.
"To the rear of the gas station, there's a Nob Hill shopping center," she said. "He could have had a getaway vehicle there. If anyone saw a man with a mask matching the description, just call us."
People with any information about this case are urged to call Livermore Police Spokeswoman Traci Rebiejo at 925-580-9665.