Seattle contractor Dathan Williams is alleged in King County Superior Court to have underbid government and private construction projects by hiring undocumented workers, falsely reporting the wages he was paying and turning over those in his employ who complained about their compensation to immigration officials.

In a lengthy investigation by the Seattle Police Department, Williams is accused of raking in more than $18,000 for a drywalling contract at the United States Postal Service’s Bellevue Carrier Annex, but undercutting workers by more than $30 per hour for the project.

The investigation into the 32-year-old JRW Structures owner was initiated by the King County Prosecutor’s Office in October 2010 after receiving a complaint from a local union.

A Seattle police officer went undercover to investigate Williams’s company after two local drywall unions identified JRW Structures as an offending subcontractor believed to be exploiting workers, according to court documents. The undercover officer also received construction training before being introduced to Williams by a cooperating witness who has done work with the subcontractor.

Court documents state Williams told the undercover officer he was fond of hiring undocumented workers for cheap labor and had contacted Immigration Customs Enforcement in the past when they demanded more money.

Williams employed the undercover officer for various construction jobs between June and November 2011. In that time, he is alleged to have encouraged falsifying unemployment claims, hiring undocumented workers, paying wages below federal contract and union standards and prevailing wage rates requirements. The court alleges he got away with paying such wages by making workers sign documents stating they are on contracts.

It is by these practices that prosecutors allege JRW Structures was able to submit bids lower than other competitors for contracts.

Rather than paying workers $35.40 per hour for the Bellevue Carrier Annex project as is prevailing wage for the federal contract, court documents state Williams paid his drywall installers 23 cents per square foot and lied about it in his reports to the Postal Service.

Williams is charged with two counts of first-degree theft, two counts of false reporting or failure to secure payment of compensation and one count of offering false instrument for filing or record. His arraignment will be Thursday.