Police are searching for a man who held up the Magic Fountain Ice Cream shop in Mattituck at about 12:20 this afternoon.
The suspect was described by police as a light-skinned male subject wearing a green jacket, black baseball cap with red trim, gray sweat pants and black sneakers.
He entered the store and demanded that an employee give him the money in the cash register, police said. The man then lifted his jacket and displayed what appeared to be a handgun in his waistband, according to a police press release.
The suspect fled from the store on foot with an undetermined about of cash, police said.
Multiple patrol units and Southold PD K-9 searched the area with negative results.
Southold detectives are continuing the investigation.
