Armed robbers hit two Medford convenience stores on Route 112 in just over 48 hours, police say.

The first happened around 9:50 p.m. Friday at a Bolla Market. Surveillance video shows two men, one armed with a gun, stealing from the cash register as the clerk stands back.

The other robbery occurred around 11:30 p.m. Sunday, at a 24-hour convenience store about a half-mile away. Video captures the armed suspects clearing out the cash register, and then hitting the clerk in the head with the gun on the way out. The clerk even pulls out money from his own pocket and offers up his wallet.

The pistol-whipped clerk returned to work on Monday, with a large gash on his forehead.

While police say they're investigating a possible link between the two incidents, they do not fit the pattern of a larger crime spree.

Anyone with information can call Suffolk Crime Stoppers at 1-800-220-TIPS.