The internist was prohibited from seeing patients as a condition of his bond and his license was suspended. He had been free on that bond until his arrest Tuesday afternoon.
An undercover officer went to Arze's office after a report the doctor was practicing again. The undercover officer says he was examined and prescribed medication by Arze.
The doctor has now been taken into custody and charged with eight felony counts of practicing medicine without a license.
He was already facing four felony and 11 misdemeanor counts in the sexual misconduct cases.
"We sent an undercover officer into Dr. Arze's office posing as a patient. Dr. Arze did examine the individual and prescribe medication for him," said Chief William Kushner, Berwyn Police Department.
Within minutes, police say, they entered his office at 6925 W. Cermak Road in Berwyn, and found the doctor examining a female patient.
Prosecutors say Arze's staff confirmed that he had been seeing between 50 and 100 patients a week since February. Given the pending case, police are concerned.
"We're very confident that there are more victims out there," said Kushner. "They need to realize that if they were touched in an inappropriate manner, beyond the parameters of a normal investigation, they are definitely victims."
Arze's co-workers would not unlock the door Wednesday nor respond to any requests for comment. But the doctor's patients defended him. Dr. Arze has cared for Maritza Torres, her husband and three children.
"He's an excellent doctor," she said. "Like I told you, it's been 10 years, and I've never heard or seen anything. For me, as a woman, my exams are perfect, professional."
"He's one excellent person," said Jose Rodriguez,, former patient. "He's a very knowledgeable person. I don't understand why he's having so many problems. I really don't."
Prosecutors consider Arze a flight risk because he has dual citizenship in the U.S. and Bolivia.