A federal grand jury in Boston has brought a fraud and racketeering case against the founder of the Arizona-based opioid maker Insys. In the criminal case filed Thursday, John Kapoor is accused along with other executives and managers of offering bribes to doctors to write large numbers of prescriptions for a powerful pain medication called Subsys, meant only for cancer patients with severe pain.

William Weinreb is the acting U.S. attorney for Massachusetts.

“It rises to a kick-back when there’s a quid pro quo, when the doctor is being paid by a company, not simply to provide information to other doctors or others who may benefit from their expertise,” Weinreb said, “but in exchange for prescribing a particular company’s medication.”

Several former Insys employees and health care providers have pleaded guilty to felony charges around the country, including in Alabama and Connecticut.