The teen suspected of raping an elderly Brooklyn woman who let him into her home forced her to “swear on a Jewish Bible” that she wouldn’t tell on him, a relative of the victim said.

“She was like a grandmother to him, and he raped her five minutes before he left,” the disgusted family member said Wednesday. “He’s an animal.”

The 82-year-old woman had offered to make suspect Asa Roberts, 18, a meal at her Coney Island Avenue South home on Monday.

“She tried to feed him,” the relative said. And after raping her, he made her “swear on a Jewish Bible” that she wouldn’t call police, the family member added.

Despite the attack, the victim still wants to return to her home after she’s healed, a neighbor said.