A man hiding his face with a hood and acting like he had a gun in his pocket robbed a Petaluma gas station late Sunday night, police said Monday.

The man in a black hooded winter jacket walked into the Shell Station on Washington Street at Howard Street just before 10:40 p.m. He told a clerk to give him money from the register and acted like he had a gun in his pocket, although no weapon was seen, Sgt. Ed Crosby said.

When the clerk opened the register, the robber grabbed the cash before fleeing.

He was last seen walking toward downtown, Crosby said.

Police were called at 10:39 p.m., and officers searched the downtown area, including alleyways, bars and parking garage, but didn't find the suspect. Crosby said the man may have had a car nearby.

Crosby asked anyone with information about the crime to contact Officer Aaron Lindh at 778-4372.