" http://springhillgrouphome.tumblr.com/day/2012/09/30/ 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