LOS ANGELES, Calif.–A physician assistant convicted using the stolen identities of doctors as part of a $10.7 million Medicare fraud scheme faces a second federal trial in November on charges of dealing in OxyContin.

After a two-week trial, David James Garrison of Leimert Park was found guilty late Friday of one count of conspiracy to commit health care fraud, six counts of health care fraud and one count of aggravated identity theft. He faces multiple years in prison at sentencing Sept. 17.

Evidence showed that 50-year-old Garrison 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.

The jury found that Garrison wrote prescriptions and ordered tests on behalf of doctors he never met and who did not give him authorization to act.

Many of the beneficiaries whose Medicare billing information was used in the scheme lived hundreds of miles from the clinics, prosecutors said.

The reason for that, according to a witness, was because the personal information of patients who lived in and around Los Angeles had been used in other Medicare fraud schemes and could no longer be manipulated.

When Garrison wrote prescriptions for power wheelchairs, for example, his associates sold the prescriptions for as much as $1,500 to crooked supply companies, prosecutors said.

The companies purchased the wheelchairs wholesale for roughly $900 each, then billed Medicare at a rate of about $5,000 per wheelchair, officials said.

Evidence also showed that Garrison ordered unnecessary diagnostic tests for Medicare beneficiaries, including tests for sleep studies, ultrasounds and nerve conduction. These tests were then billed to Medicare by crooked diagnostic testing companies that paid conspirators kickbacks, prosecutors said.

As a result of the scheme, Garrison and others helped submit more than $18 million in false and fraudulent claims to Medicare, which paid out roughly $10.7 million on those claims, authorities said.

Garrison faces a second trial Nov. 6 as a result of his alleged involvement with another medical clinic where prescriptions for the opiate painkiller OxyContin were distributed without medical need, officials said.