GULFPORT (AP) — Authorities say a prescription drug ring at an outpatient psychiatric center has led to the arrest of three health care workers.

News outlets report 34-year-old Andrea Reene Opoku, 29-year-old Nikita Marie Piernas and 36-year-old Tyrone Leonard Thomas were arrested Wednesday in connection with a 42-count indictment that led to the arrest of nine others. The workers were employed at Merit Health’s Gulf Oaks Outpatient Center in Biloxi.

They are accused of obtaining fraudulent prescriptions for a variety of opioids and other drugs. They each face multiple charges including fraud and conspiracy to distribute or dispense controlled substances outside the scope of professional practice.

According to the indictment, Opoku led the operation by giving out prescriptions with Piernas’ help.