Dr. David H. Newman seemed to have it all: an impressive post in emergency medicine at Mount Sinai Hospital, a prominent and growing public presence as an expert in health care reform, a wife who is a doctor, two young sons, and a gracious home in the New Jersey suburbs.

So when he was arrested on Tuesday and charged with sexually abusing two patients under his care in the emergency room, the reaction from his wide circle of colleagues was disbelief.

“I’ve gotten a whole bunch of frantic emails from around the world saying: ‘What’s going on? How could this be?’” said Dr. Jerome Hoffman, a professor emeritus of medicine at the University of California, Los Angeles, who has known Dr. Newman for more than a decade. “Everyone is saying: ‘David? This doesn’t make any sense.’”

Dr. Newman, 45, has been accused of drugging, groping and masturbating on a female patient and groping another in episodes several months apart, the authorities said.