LOS ANGELES (CNS) - A Los Angeles physician's assistant -- who was previously convicted of using the stolen identities of doctors as part of a $10.7 million Medicare fraud scheme -- is expected to plead guilty to playing a role in a separate health care fraud operation that illegally obtained and sold nearly 1 million OxyContin pills.

David James Garrison, of LeimertPark, has agreed to enter his plea Wednesday before U.S. District Judge Dean D. Pregerson to one federal count of conspiracy to divert and distribute the opiate painkiller without medical need, according to a signed agreement with prosecutors obtained today by City News  Service.

In exchange for his expected plea, prosecutors plan to recommend that Garrison be sentenced to at least eight years in custody to run concurrently with the six-year sentence he was handed previously.

A Los Angeles federal grand jury returned an updated indictment last October charging Garrison and 19 others with participating in a drug trafficking organization that obtained the pills in part through fraud against public insurance programs such as Medicare.

The indictment alleges that the Lake Medical Group, near downtown Los Angeles, was a base of operations for doctors who wrote OxyContin prescriptions for Medicare and Medi-Cal beneficiaries, as well as other patients, who did not need the drug.

The pills were obtained from Southland pharmacies, some of which submitted fraudulent bills to the public insurance programs, according to federal prosecutors. Members of the conspiracy allegedly resold more than 900,000 OxyContin pills on the street, reaping an estimated $17 million in profits.

To deal with the large amounts of cash generated from the illegal OxyContin sales, some of the defendants “structured” cash deposits by making bank deposits in amounts of $10,000 or less to evade bank reporting requirements, prosecutors allege.

Other defendants used proceeds from drug sales to gamble at casinos to purchase automobiles and jewelry and to buy more OxyContin, according to court documents.

The scheme was allegedly orchestrated by Mike Mikaelian and Anjelika Sanamian, who operated the clinic on

West Eighth Street
. The indictment describes LakeMedical as a “prescription mill” that both generated prescriptions for unneeded OxyContin and submitted claims to Medicare and Medi-Cal for medical services that were unnecessary or were never performed.

The indictment alleges that Dr. Morris Halfon and other physicians based at LakeMedical knowingly diverted the OxyContin by prescribing it to “patients” who did not have a medical need.

The indictment further alleges that a significant percentage of the prescriptions were filled at Southland pharmacies owned and operated by Arcadia pharmacist Theodore Yoon and five other defendants.

A jury trial in the case is scheduled for late September.

Garrison, 51, was convicted in June 2012 of health care fraud and identity theft and sentenced last September to the six-years federal prison term. Evidence at trial showed that he worked at phony medical clinics that operated as prescriptions mills and trafficked in bogus prescriptions and orders for medically unneeded equipment such as power wheelchairs, and diagnostic tests.