NEW YORK (CBSNewYork) — A teenager was in jail Monday night after coming to his mother’s defense in the Bronx.

As CBS2’s Valerie Castro reported, crime scene tape was still over the door Monday night the University Avenue apartment in University Heights where police sources said the 18-year-old man strangled Stanley Washington, 43, who was allegedly attacking the teen’s mother.

It happened early Monday morning, sources said.

Sources said the 18-year-old awoke to find his mother’s ex-boyfriend assaulting her in their family home. He intervened, and police said he choked Washington until the older man passed out.

Washington was pronounced dead at the scene once police arrived.

Neighbors said the young man is never in trouble and always friendly.

“He’s a good kid. He went to school, I see him sometimes in the morning — he’d go off to school and that’s it,” a neighbor said.

Outside the 52nd Precinct police station, the teen’s family did not say very much to CBS2’s cameras.

“We can’t talk to you right now. We got to go inside,” a family member said.

But family members later said off camera that the 18-year-old would never intentionally harm someone.