A man robbed a Mastic Beach market at knifepoint Monday — but after reviewing surveillance video Suffolk County police said it’s not the work of a knife-wielding bandit who’s robbed at least 17 businesses on Long Island in recent months.

The robbery occurred at Country Market on Whittier Drive near Neighborhood Road at about 9:30 p.m., police said. The suspect entered the store, displayed a knife, told the clerk to open the drawer — then stole cash and cigarettes before fleeing on foot.

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But police said the suspect’s physical description — the Mastic Beach robber is about 5-foot-6 and about 230 pounds — gives them good reason to believe it’s not linked to the pattern robberies committed by the knife-wielding robber who’s hit businesses in Nassau and Suffolk since March 1.

The FBI has joined the probe into the robberies involving a masked man who has hit at least seven Dunkin’ Donuts shops, two 7-Elevens, two Subway sandwich shops and two Carvel ice cream stores.