Police are investigating whether a string of recent armed robberies in Nassau are connected.

Police say a man walked into a 7-Eleven on Old Bethpage Road in Old Bethpage shortly after midnight on Thursday. They say the man had a large kitchen knife and demanded cash. The amount of money he got away with is unknown.

Officials say they are looking into whether the suspect is the same person who robbed two Dunkin' Donuts earlier in the week.

Two hours before the 7-Eleven robbery Thursday, police say a man with a similar description used a handgun to rob a Dunkin' Donuts in North Bellmore. 

On Monday night, a man with a similar description to the other incidents robbed a Dunkin' Donuts in Plainview with a kitchen knife.

Anyone with information is asked to call Nassau Crime Stoppers at 1-800-244-TIPS.