Shot 07/07/2011.## A man spent four years in prison for a robbery he did not commit because of an error in DNA testing, according to the Las Vegas Metropolitan Police Department Forensic Lab.   Metro said an accidental switching of DNA samples within the LVMPD Forensic Lab in a 2001 case, incorrectly identified then 18-year-old Dwayne Jackson as the suspect who committed a robbery. Jackson served four years in prison after accepting a plea agreement. He was then released in 2006. Metro said when they discovered their error they began an immediate investigation and contacted the District Attorney’s Office to begin the process of clearing Jackson's record.##