Officials are looking for a woman who went missing after leaving a South Jersey psychiatric hospital with an unidentified woman who wasn't a known family member.

Gloucester Township police said this morning that 51-year-old Cheryl Keys remains missing nearly three weeks after she signed herself out from the Northbrook Behavioral Health Hospital with a day pass.

Authorities believed she left the hospital, located at 425 Woodbury Turnersville Road in Blackwood, with a family member at 10:45 a.m. on Nov. 13.

However, Keys never returned to the facility and investigators later determined that the woman she departed with wasn't a known relative, police said.

Keys appeared to leave the hospital with the woman willingly, authorities said.

Keys was described as black, 5 feet, 4 inches tall and weighing 250 pounds. She has brown hair, and was wearing matching black pants and a zip-up jacket with white stripes when she left the hospital. She was also wearing sneakers and carrying another jacket.

The woman she left the facility with was wearing a gray jacket, blue shirt and blue jeans. She was driving a red, four-door car.

Keys is known to spend time in Camden.

Anyone with information is asked to call police at 856-228-4500 or the department's anonymous tip line at 856-842-5560.