SPRINGFIELD, Mass. (AP) -- Police say three masked men who tried to rob a Chinese restaurant in Massachusetts ran away empty handed because they couldn't figure out how to open the cash register.

The men, one of whom had a gun, entered the Peking House restaurant in Springfield at about 8 p.m. Monday.

A female employee saw the gun, ran out the back and called police.

Police say the thieves couldn't figure out how to open the cash drawer, so they took off.

Police scoured the neighborhood but couldn't find the suspects, and the attempted theft remains under investigation.