Smithfield police were informed of Scott M. Lyman's death Tuesday by his family and Las Vegas police, The Salt Lake Tribune reported Saturday.
Lyman had been arrested Feb. 25, hours after the alleged victim, who was not one of the dentist's patients, came forward, the newspaper said. He had not been charged by prosecutors.
Lyman had been hospitalized on life support March 8 and was taken off the machines Tuesday, Smithfield Police Chief Johnny McCoy said. Initial evidence pointed to an overdose, he said.
Lyman's 38-year-old brother Matthew Lyman had pleaded guilty in 2007 to fondling the breasts and buttocks of two female patients who were under anesthesia. He committed suicide after finishing his prison term, McCoy said.