"He's a nice kid, really quiet, sticks to himself," a neighbor said.
That's how neighbors describe the 13-year-old boy who may have saved his mother's life.
It was early Monday morning when police say 48-year-old Norman Shields entered into the house on Selden Road in Mastic Beach.
Inside were Shields' ex-girlfriend, 31-year-old Natasha Bivens, and her current boyfriend.
"Female caller told police that her ex-boyfriend had entered the home with a handgun and had an altercation with her and her current boyfriend," said Lt. Jack Fitzpatrick, Suffolk County Police.
A shot was fired.
Police say Shields began attacking Bivens.
Bivens' teenage son, most likely hearing the commotion, got a knife from the kitchen and stabbed Shields in the chest, killing him.
Latisha Hatcher goes to school with the boy.
"I don't want it to go out that he did it on purpose because he was protecting his mom and his sister," said Latisha Hatcher, neighbor.
Bivens and Shields' child, a 4-year-old girl, was in the home at the time of the incident and was not injured.
The current boyfriend apparently fled the scene.
The investigation is continuing. Anyone with information is asked to call the Homicide Squad at 631-852-6392 or anonymously to Crime Stoppers at 1-800-220-TIPS.