San Antonio police are asking for the public's help in finding a man who they said robbed a near Northwest Side convenience store.

According to police, the man robbed the Diamond Food Mart, located in the 7800 block of Callaghan Road, on Oct. 20.

Store clerks told police investigators the man had been in the store twice that day prior to the robbery.

They said he returned a third time, went into a bathroom, then came out and threatened the clerk and demanded money.

The man fled with an unidentified amount of cash and a 12-pack of Big Red. He left the scene in a black Nissan Altima with paper tags.