A New York City dad massacred his family early Saturday morning, marching from room to room, shooting his two daughters, his girlfriend and her mother in the head before fleeing, police said.

The only survivor is the couple’s 12-year-old daughter, who managed to call 911 and open the door for police despite being shot in the head and having the bullet exiting through her eye, sources said.

The girl was rushed to Long Island Jewish Medical Center in critical condition.

Jonathan Walker, 34, a hulking, 6-foot-6, 260-pound nightclub bouncer, fled the bload-soaked 5 a.m. scene in Springfield Gardens, Queens. Just before noon, his body was found inside his car with a gunshot wound to the head, in a wooded area near John F. Kennedy Airport, sources said.

It’s unclear what made Walker, who is originally from Buffalo and played basketball professionally in Europe from 2008-2009, suddenly snap.

He told a friend he was “going home to watch Netflix with the family,” said City Councilman Donovan Richards, who called the murder scene “truly horrific.”

“We’ve heard he was out with a friend. He told his friend he was going to get some beers and going home to watch Netflix with the family. We don’t know what made him snap when he came in,” Richards said.

The bodies of Viola Warren, 62, and her daughter, Shantai Hale, 31, were discovered in one bedroom, while little 7-year-old Kayla Walker was found in another bedroom inside the 148th Avenue home, police said.