FBI agents are following up on a KING 5 Investigation that exposed an Enumclaw official's alleged theft of public money.

Editor's Note: The above video first aired in early May as part of KING 5's ongoing investigation into King County drainage districts.

Two Seattle FBI agents were in Enumclaw last week, collecting evidence in a public corruption case.

They’re looking into the alleged theft of tax money by the longtime commissioner of King County Drainage District No. 5.

Senior officials at the Enumclaw Police Department said the agents visited police headquarters on Wednesday and picked up the department’s detailed case files against Allan “Ben” Thomas.

Enumclaw police started investigating Thomas, the longest-serving Drainage District 5 commissioner, in late 2017.

Police submitted their case to the King County Prosecutor’s Office, but no charges have been filed against Thomas.

“There [are] no formal charges at this point. He’s free and clear (until a charging decision is made),” said Enumclaw Police Commander Tony Ryan.

But the case took on new life after the KING 5 Investigators exposed Thomas’ alleged scheme that funneled taxpayer money into his private bank accounts.

KING 5’s “Money Down the Drain” series revealed public documents, including police search warrants executed on two personal bank accounts, that showed $413,000 in tax money Thomas collected ended up in bank accounts for his personal use.

King County Drainage District No. 5 is a “special purpose district” which collects tax money from 600 property owners in the Enumclaw area to maintain a century-old trench system. The 18 miles of ditches were designed to help control flooding in the rural south county area.

Thomas has denied any wrongdoing.

Enumclaw police records show that Detective Nona Zilbauer zeroed in on a contractor that Thomas claimed was dredging and clearing the district’s trenches.

Also see | State fraud report calls troubled King County drainage district 'unauditable'

The detective learned that “A Conservation Services” was a company that Thomas started under his son’s name in 2012. But his son, Alex, told Zilbauer that he had not done any work for his father since 2012.

Zilbauer’s records show that A Conservation Services continued to bill the county through 2018 for supposed ditch-clearing.

A subsequent report by the office of Washington Auditor Pat McCarthy found that only 4% of the approximately $80,000 in taxes that Thomas collects annually on behalf the district is spent on legitimate work.

Commander Ryan said it remains unclear if the Enumclaw Police Department will continue to pursue the case, or if it will all be handed over to federal authorities.

On Monday, King County councilmembers began confirming replacements for Thomas and commissioners in King County Drainage District numbers 6 and 13.