Kenneth Litwack, 71

Kenneth Litwack, 71

A search continued Friday for a Newport Beach doctor who went missing near Tucson, Ariz.

Dr. Kenneth Litwack, 71, an infectious disease physician, checked into the Sierra Tucson treatment center about 3 p.m. Aug. 12, and went missing from the facility Tuesday afternoon, said Litwack's wife, Louise Litwack.

Litwack has a practice on Superior Avenue near Hoag Hospital.

Friends and family members have gone to Tucson to search for Litwack, said family friend Ben Sheffner, and authorities in Tucson were searching by ATV and air.

His disappearance is a "complete mystery. That's why everyone is so concerned," Sheffner said.

Louise Litwack said a dog search for her husband began about 6 a.m. Friday.

Clinic personnel called Louise Litwack on Tuesday afternoon to say that her husband hadn't been seen for at least an hour. Workers informed her that Litwack had left behind all his personal possessions, including his wallet and watch, but noted that an American Express card was missing.

Louise Litwack said her husband needs his high blood pressure medicine, and friends are concerned about him being in the desert without provisions.

Litwack was being treated for chronic pain he had as a result of foot neuropathy, although it did not affect his ability to walk, Louise Litwack said.