Several pharmaceutical executives and managers, formerly employed by Insys Therapeutics, Inc., were arrested last December on charges that they led a nationwide conspiracy to bribe medical practitioners to unnecessarily prescribe a fentanyl-based pain medication and defraud healthcare insurers, according to a release from the Department of Justice.

U.S. Senator Claire McCaskill of Missouri –  a senior member of the Senate’s Homeland Security and Governmental Affairs Committee — announced an investigation into the business practices of the manufacturers of America’s top-five prescription opioid products. One report from the investigation titled  “Fueling an Epidemic: Insys Therapeutics and the Systemic Manipulation of Prior Authorization,” was released earlier this month. Other manufacturers under investigation include Purdue, Johnson & Johnson, Mylan, and Depomed.