A Ventnor woman has confessed to beating her mother and grandmother to death with a nightstick in an attack at their high-rise apartment at the New Jersey Shore, according to documents obtained Wednesday.

Heather Barbera, 42, authorities said, told police she killed the women, then took cash and credit cards from them, and eventually made her way to New York City, where she was arrested after four days on the lam.

While in New York, she made purchases with the stolen credit cards — and that allowed law enforcement officials to track her down and charge her in the deaths of Michelle Gordon, 67, and Elaine Rosen, 81.

Surveillance video showed Barbera leaving the women's Ventnor condo on July 7. Authorities say she later went to Atlantic City, then to New York.

She was arrested on July 11 after being spotted by officers at the New York Port Authority Bus Terminal. She was being held Wednesday while awaiting extradition to New Jersey, where she faces murder, robbery, and other charges. She declined to waive an extradition hearing in New York City, which is set for Aug. 8 in Manhattan.

Barbera's lawyer, Ariel Schneller of the Legal Aid Society​ in New York, declined to comment on the charges Wednesday.

Barbera was being held in the Rose M. Singer Center, a women's facility on Rikers Island, where she was in protective custody, officials said.

Richard Rosen, Barbera's uncle, discovered the bodies of his sister and mother on July 8. He said he had warned the two not to let his niece live with them in their eighth-floor apartment in Vassar Square Condominiums.

Rosen has said that his niece had emotional problems and that he believes she was addicted to prescription pills.

"It's unimaginable," he said in an earlier interview. "It was horrible. They were both on the floor. There was blood all over. I was hoping they were alive, even though they were dead."