A Long Island teenager fatally stabbed his mother's former boyfriend when he showed up to their Mastic Beach home and threatened her with a handgun, authorities say.
Suffolk County police say the ex-boyfriend entered the Selden Road home of the teenager's mother and confronted her and her new boyfriend around 4 a.m. Monday.
When the intruder threatened the woman with a handgun, her teenage son intervened and stabbed the man, police said. The intruder was pronounced dead at Brookhaven Memorial Hospital.
The Suffolk County Homicide Squad investigation is ongoing.
It was not immediately clear if the teenager would face charges.