SEATTLE (AP) – An obscure, now-former King County official has been arrested amid a federal corruption investigation.

U.S. District Court records show that Allan “Benny” Thomas, who served as the longtime commissioner of King County Drainage District No. 5, was arrested Monday along with his wife, Joann Thomas, on a mail fraud charge. The FBI said in written complaint that the couple cheated the district’s taxpayers of nearly $500,000 from 2012 to this year.

A KING-TV investigation last spring revealed that money supposedly being used to maintain 18 miles of stormwater drainage trenches around the Enumclaw area instead went to a company controlled by the Thomases. It was spent on personal expenses like livestock feed and equipment for his 150-acre dairy farm.

Thomas resigned in May, after 35 years as commissioner.