Arthur C. Bieganowski, at one time the busiest workers’ compensation doctor in Texas, was a medical miracle of sorts, according to the authorities.

By their account, his bills reflected that he sometimes handled up to 200 patients a day. For an eight-hour span, that works out to one treatment visit every 2.4 minutes. "Physically impossible," said Assistant U.S. Attorney Debra Kanof in El Paso, Texas.

Ms. Kanof prosecuted the doctor and nine other people after an investigation employing an undercover sting by insurers and the FBI. The physician is now in jail awaiting sentencing this August on a variety of charges related to $43 million in billings.

Officials said Dr. Bieganowski is one of the latest health care providers caught by the FBI and state and local law enforcement as Texas ramps up efforts to put a lid on its soaring workers’ comp costs.