HARLEM, Manhattan (PIX11) — The 18-year-old man sought for allegedly stabbing a 16-year-old girl to death in Harlem dated the teenage victim, police said.

Zyaire Crumbley allegedly fatally stabbed Saniyah Lawrence in the neck on Sunday, officials said. Police continued their search for Crumbley on Monday evening.

Lawrence was attacked inside a first-floor apartment on Adam Clayton Powell Jr. Boulevard near West 135th Street, police said. A neighbor, who did not want to be identified, said the apartment was a trouble spot. She often heard arguing, but never expected something like the deadly stabbing.

“I always had concerns about what was going on in that apartment,” she said. “It definitely made me fearful for who was in the apartment, so to hear that someone lost their life, it definitely made me sad.”

Crumbley has a criminal history, sources said. There was also a history of domestic violence in the couple’s relationship.

Stephanie McGraw, founder of We All Really Matter, a community organization that helps victims of abuse, said she’s been helping Lawrence’s mom. She said she was called Sunday night to stay with the victim’s mother and help her.

McGraw said there’s no minimum or maximum age when it comes to domestic violence. She said it’s happening to more and more young people.

“To all of ya’ll young girls out there right now, domestic violence is real, it’s killing,” she said.

If you or someone you know is a victim of domestic violence, click here for help.

Submit tips to police by calling Crime Stoppers at 1-800-577-TIPS (8477), visiting crimestoppers.nypdonline.org, downloading the NYPD Crime Stoppers mobile app, or texting 274637 (CRIMES) then entering TIP577. Spanish-speaking callers are asked to dial 1-888-57-PISTA (74782).