At about 11:55 a.m., police received a 911 call from a motorist who said another motorist pointed what appeared to be a handgun at him in a traffic dispute on southbound Nicolls Road, near the north service road of the Long Island Expressway.
A Highway Patrol officer received a description of the suspect, including the type of vehicle and a license plate number.
Registration was for a gray 2012 Volkswagen in Northport, police said, and the information was broadcast via police radio. Northport Village police stopped the vehicle and detained the suspect, Brian Deuchar D'Angelis, 36, of 68 Lakewood Ct., Moriches.
The other motorist identified Deuchar D'Angelis, who was arrested on charges of menacing and criminal possession of a weapon; police said they found an imitation pistol in the Volkswagen, which was impounded for evidence.
Deuchar D'Angelis is scheduled to be arraigned Wednesday at First District Court in Central Islip.