A former Memphis police officer who pleaded guilty to a drug charge resulting from an FBI sting was sentenced in federal court on Wednesday to four years in prison.

An attorney for former officer Michael Shane Sinnock argued for leniency, contending in court documents that Sinnock wanted to purchase 20 painkillers and two pounds of marijuana for his wife, who suffers from sciatic nerve damage and chronic pain.

     Former Officer Michael Shane Sinnock 

"The purchase of these drugs was not for public distribution or profit, but was for the treatment of pain suffered by his wife," the attorney, Lee Gerald, argued.

Gerald also reported that the FBI's confidential source in the case was an old friend of Sinnock's. The FBI source during the investigation sold Sinnock 20 Lortab pills, rendezvousing with the on-duty officer at the Eastgate Shopping Center in December 2011, where he was arrested, according to a court affidavit filed by an FBI agent.

See how many Memphis police officers and employees have previously  been charged with corruption.