Police are calling them a series of pattern robberies, believed to be the work of one suspect, pulled off in the past two weeks across Suffolk County.

Now, they're asking the public's help in catching the robber -- a man in his late 20s or early 30s, armed with a black handgun.

Suffolk County police said most of the targets have been gas stations, though investigators believe a robbery at a Jamba Juice bar in Stony Brook also is part of the string.

Police said that, as part of the pattern, the robber enters an establishment, pretends to purchase at item and then, when the employee opens the cash register, produces the handgun -- and demands cash.

The suspect then flees, police said, possibly to a waiting vehicle nearby the location.

The gas stations robbed in the spree are in Eastport, Calverton, Mastic, North Babylon, St. James, Dix Hills and Bohemia. No one has been injured in the robberies.

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The suspect is described as being between 5-foot-10 and 6-foot-2 with a thin to medium build. He usually wears a dark-color or gray hooded sweatshirt, police said.

Police ask anyone with information about the robberies to call Crime Stoppers at 800-220-TIPS. All calls will remain confidential.