A maniac who raped a woman in a Queens alley threatened to kill the woman if she didn’t comply, police sources said Monday.

“If you scream, I’m going to snap your neck,” the perv growled as he grabbed the 27-year-old around 4 a.m. Saturday near 163rd Street and 89th Avenue in Jamaica.

The victim told cops she was walking alone after leaving the Tropical Fantasy Bar & Lounge about a half-mile away on Jamaica Avenue when the man approached her from behind.

He dragged her into the alley and told her to keep quiet. She tried to fight him off, but he hit her and pulled down her pants, snarling, “I won’t kill you if you do what I want.”

He had forcible sex with her and then fled, cops said. She was taken to NYC Health + Hospitals/Queens for injuries to her head, body, arms and legs, cops said.