A Los Angeles man was sentenced to six years in prison last week for his role in a power wheelchair scam, topping what prosecutors say has been a series of Medicare fraud cases.

David James Garrison, 50, a former physician assistant, was found guilty by a federal jury for his role in submitting $18.9 million in fraudulent Medicare claims for power wheelchairs and other equipment.

The wheelchair case is the third time Garrison has been accused of Medicare fraud.

In 2009, Garrison pleaded no contest to tax evasion for his role in what prosecutors described as a fraudulent medical clinic. He pleaded not guilty in October to charges that he forged prescriptions as part of an OxyContin ring that sold 1 million pills on the streets. That case is ongoing.

Garrison's attorney did not return a call for comment about the cases.

Garrison's physician assistant license lapsed in 2009, said Russ Heimerich, a spokesman for the Department of Consumer Affairs, which oversees many state licensing boards. He said the board examined the tax evasion case and did not see it as grounds for discipline.

According to court documents, Garrison's cases involved the use of “cappers” or “marketers” who recruited Medicare beneficiaries to submit to unneeded care or hand over their personal information. That information was used to bill the program for medications, services or supplies that the patients didn’t need.

In the wheelchair case, prosecuted by the Los Angeles U.S. attorney's office, one witness testified that marketers had to recruit beneficiaries as far as 300 miles from Los Angeles because so many local people had already been used in other fraud schemes.

In the first health fraud case linked to Garrison, he was described as an “at large” suspect in October 2007 when then-Attorney General Jerry Brown announced arrests in a $1.5 million health fraud scam.

"The suspects create a fake healthcare clinic to line their own pockets rather than help the sick and elderly," a 2007 statement from Brown said.

In that case, Garrison was accused of ordering medically unnecessary diagnostic tests at Scott Medical Center in Burbank, where he had worked since 2003. Medicare and Medi-Cal beneficiaries were recruited to go to the clinic, where expensive tests were ordered and billed to the government.

Garrison pleaded no contest to tax evasion in 2009 related to his earnings from the clinic.

When federal authorities arrested Garrison in the wheelchair scam in 2010, he was also charged for keeping a .357 handgun in an unlocked hatbox near the front door of his Inglewood apartment. Garrison pleaded no contest in 2010 to being a felon in possession of a firearm.

Heimerich said while the gun case was prosecuted by the state, it arose from a federal arrest that did not trigger a notice to the physician assistant licensing board. Also, he said a state court clerk was required to notify the board but did not.

During a two-week trial, evidence showed that Garrison worked at Van Nuys and Los Angeles clinics where he wrote prescriptions and ordered tests on behalf of six doctors, including one whose photo he couldn't identify.

With Garrison’s prescriptions in hand, co-defendant Edward Aslanyan sold them for $1,000 to $1,500 to owners of about 50 different medical equipment firms. The medical supply companies used the prescriptions to buy the chairs from wholesalers for about $900, then billed Medicare for up to $5,000 per chair.

The hefty profit margins have made the wheelchairs a major target for Medicare fraud throughout the U.S. Garrison and Aslanyan wrote and sold the prescriptions from March 2007 to September 2008, prosecutors said.

A jury found Garrison guilty of conspiracy to commit health care fraud, six counts of health care fraud and one count of aggravated identity theft. Aslanyan pleaded guilty to his role in the scam and was sentenced to six years in prison as well.

According to Assistant U.S. Attorney David Kirman, the medical equipment firms included one run by a pastor, Christopher Iruke, who relied on members of the Arms of Grace Christian Center to perpetuate Medicare fraud.

Court documents show that two Garrison acquaintances told a defense investigator that he was their children's track and field coach and was honest and well-liked. One parent said Garrison's "integrity is unshakable."

In November, Garrison faces trial on drug charges related to a clinic that allegedly forged prescriptions for the addictive and powerful painkiller OxyContin, which was sold on the street for up to $30 per pill.

Prosecutors say he worked there from the summer of 2009 to February 2010. He has pleaded not guilty.

In that case, federal prosecutors allege that Garrison worked as a physician assistantat an Eighth Street clinic in Los Angeles where recruiters offered Medicare and Medi-Cal patients cash or free medical care to go to the clinic.

There, Garrison and others met briefly with patients and issued prescriptions of 90 top-strength OxyContin pills. Other members of the alleged drug ring went with the patients to obtain the pills from pharmacies and gave them to another man who sold them on the street.

Garrison told investigators that he issued the prescriptions if he felt the patients needed pain medications or had been taking OxyContin.

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