A nephew of the alleged mastermind behind the largest government theft case in the District’s history became the first defendant to be sentenced to prison Wednesday.

Ricardo Walters, 33, of Fort Washington, was ordered to serve six and a half years for helping to launder the more than $48 million that was stolen from the D.C. Office of Tax and Revenue. Walters was taken into custody at the federal courthouse in Greenbelt to begin serving his sentence.