Six Michigan doctors have been charged with insurance fraud and unnecessarily prescribing opioids to patients in a $464 million scheme, according to court documents filed this week by federal prosecutors.

The 56-count indictment, filed on Tuesday and made public on Thursday, named Dr. Rajendra Bothra, 77, of Bloomfield Hills, who owned and operated the Pain Center USA in Warren and Eastpointe, Mich., and the Interventional Pain Center in Warren. The other five doctors were employed by the clinics, which catered to patients with joint and spinal injuries.

As part of the scheme, Dr. Bothra “sought to bill insurance companies for the maximum number of services and procedures possible with no regard to the patients’ needs,” the United States attorney’s office for the Eastern District of Michigan, which filed the charges, said in a statement on Thursday.

Jeffrey Crapko, a lawyer for Dr. Bothra, declined to comment on the case. An after-hours operator at the Pain Center USA said the federal authorities had raided and closed the offices.