Police are investigating possible links between early morning armed robberies at two different 7-Eleven stores Saturday and Monday.

In both robberies, a man holding a handgun inside a white 7-Eleven sack confronted the store clerk and then bound him with duct tape in a back room, according to a police report.The two 20-year-old clerks told police they could hear several people going in and out of the store during the robberies before the armed man in each case returned to check on the clerk before leaving.

Three males were inside the store about 30 minutes during the Monday robbery at 7820 S. Seventh East. The clerk said he turned around while bound with the tape and saw a second man, who then got angry and banged the clerk's head against the wall repeatedly until a third man came and stopped the attack.

In the Saturday robbery, at 8500 S. State, the robber stuffed three $10 bills in the clerk's jacket pocket before leaving the store and said "this is for your trouble," the police report said. The clerk said he also heard a woman's voice in the store during the robbery.

Cash and money orders were taken from both stores.