The 18-year-old woman allegedly killed by her boyfriend in a Brooklyn home was strangled and sexually molested before her neck was snapped, according to horrific new details revealed in court documents Sunday.

Dylan Diaz, 26, was remanded into custody after his arraignment in Brooklyn Criminal Court on second-degree murder charges in the vicious death Damaris Maravilla, who was found face down at his Bensonhurst address on Friday morning.

According to the criminal complaint, Diaz wrapped his arm around his girlfriend’s neck “and squeezed until… (she) lost consciousness.”

With the victim still unconscious, he then allegedly penetrated her with his fist, the court doc states.

“The defendant then took …. Damaris Maravilla by the neck, who was still unconscious and snapped … Damaris Maravilla’s neck,” according to the complaint.

The young woman was pronounced dead at the home at 1515 West Sixth Street after police arrived around 10:15 a.m. Friday, cops said.

cops said Maravilla and Diaz lived separately but on the same block.

Diaz was arrested at the scene.

He is being held without bail at Rikers Island pending a return court appearance Wednesday, according to court records.

A GoFundMe page created by the slain woman’s sister, Juliet Maravilla, seeks to raise $50,000 to pay for the victim’s funeral expenses.

“We want to give my sister Damaris Maravilla the memorial she deserves to honor her memory and say our goodbyes,” her sister wrote.