A New Jersey woman bludgeoned her mother and grandmother to death, then went on the lam to Manhattan, where she was arrested, police sources told The Post.

Heather Barbera, 42, beat the women inside their Ventnor apartment on July 7, swiped their cash and credit cards, then fled to Atlantic City and, later, New York, sources said.

Cops picked up Barbera’s trail when she used her mother’s credit card at the Salisbury Hotel on West 57th Street on July 11, according to sources.

She made other purchases with the card as she walked toward Times Square, leaving cops a trail of virtual breadcrumbs that eventually led them to Barbera sitting on steps near the Port Authority Bus Terminal, sources said.

Shortly after her arrest that day, Barbera allegedly confessed to using a nightstick to murder her mother, 67-year-old Michelle Gordon, and grandmother, 81-year-old Elaine Rosen, according to the Philadelphia Inquirer.

“It’s unimaginable,” said Barbera’s uncle, Richard Rosen, who found the bodies July 8.

“It was horrible,” he told the Philadelphia Inquirer. “They were both on the floor. There was blood all over. I was hoping they were alive, even though they were dead.”

Rosen claimed that Barbera has unspecified emotional issues, and believes that she is addicted to prescription pills, according to the report.

Barbera is on Rikers Island awaiting extradition to New Jersey, where she faces charges including murder and robbery, according to the Inquirer.