A Mastic man has been arrested in the fatal stabbing Friday afternoon of Trevor Bender, 17, during a fight on a street corner, Suffolk County police said.

Homicide Squad detectives arrested Michael Dennis, 19, of 1035 Mastic Rd., on a charge of manslaughter, police said late Saturday.

Bender, 17, of Mastic was a passenger in a car that got stuck in traffic Friday on Mastic Road in Mastic, police said. Bender and his friend, an 18-year-old driver, got out of the car and the two approached the group, whom they knew, standing at the corner of Mastic Road and Moriches Avenue where an argument ensued.

"They were just really cursing at each other," Det. Lt. Kevin Beyrer of the Suffolk Homicide Squad said Friday.

The argument escalated into a fight.

"One girl smacked Trevor. He punched her. Then the second girl punched him," Beyrer said.

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A third person from the group stabbed Bender once in the chest, police said, then fled on foot.

The stabbing occurred about 5:10 p.m., police said.

A fire chief, who was also stuck in the same traffic jam, saw what happened and called for an ambulance, Beyrer said. The fire chief and Bender's friend tried to stop the bleeding until the ambulance arrived.

Bender was taken to Brookhaven Memorial Hospital Medical Center in East Patchogue, where he was pronounced dead Friday, police said.

Dennis, who was arrested Saturday, is being held overnight at the Fifth Precinct for arraignment Sunday at First District Court in Central Islip.

With Rosemary Olander