Nassau County police are investigating the attempted robbery of a Freeport deli and a robbery of a Baldwin gas station -- which happened late Sunday in about a 20-minute span -- as part of a string of related pattern robberies.

A department spokesman said the two events are being investigated as part of a pattern of about 10 robberies in which a thinly built masked gunman, about 5 feet 8 and wearing a black, hooded sweatshirt, enters a 7-Eleven, convenience store or gas station. He flashes a black handgun, demands money and then flees on foot.

The suspect Sunday first tried to rob the Village Express deli on North Main Street in Freeport at 10:46 p.m.

But a customer entered the store and the suspect fled west on Dean Street without getting any cash, police said.

At 11:07 p.m., the same suspect entered the Citgo on Sunrise Highway in Baldwin, selected two items from shelves, went to the counter, displayed a black handgun and demanded money from the register.

Police said the clerk, a man, 45, placed the cash in a black plastic bag, along with the two unspecified items, and said the suspect then fled south on Milburn Avenue.

Investigators believe that same person is responsible for a string of similar robberies that date back to April 15 and include the holdup of an East Meadow delicatessen, as well as robberies of convenience stores and other 7-Elevens in Merrick, Freeport, Valley Stream and West Hempstead in recent weeks.

Police are asking anyone with information regarding the crimes to call Crime Stoppers at 800-244-8477. All calls will remain confidential.

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