The A-Plus Market at 555 Niagara St. was robbed of $47 at 1:45 p.m. Sunday, police said.
A security camera videotaped the robbery in the market, which is across the street from the former Precinct 10 station.
William Abbott told B District officers that a man bought a bottle of beer, then requested change for a dollar.
While the employee was complying, the man jumped over the counter and grabbed the money out of the cash register. He fled north on Niagara.