(Reuters) - Washington State’s Attorney General on Wednesday sued private prison company Geo Group Inc for violating the state’s minimum wage laws by paying detained immigrants a one dollar a day or less for work they do while in detention at one of the company’s federal facilities.

An ICE detainee rests his hands on the window of his cell in an immigration detention center, run by the Geo Group Inc (GEO.N), in Adelanto, California, April 13, 2017. REUTERS/Lucy Nicholson

The lawsuit, filed in state court in Tacoma, follows a months-long investigation by the Attorney General’s office that found immigrant detainees at the Northwest Detention Center in Tacoma who prepared food and did maintenance in the center sometimes only received only snacks for their work.

Geo Group has owned and operated the 1,575-bed facility for U.S. Immigration and Customs Enforcement (ICE), which holds immigrants awaiting court hearings or deportation, since 2005.

ICE’s 2011 National Detention Standards require the company to pay detainees at least $1 per day for their labor.

The lawsuit is seeking, however, to enjoin Geo from paying detainees less than the state’s minimum wage of $11 per hour.

Washington’s minimum wage laws do not apply to state jails, but the Attorney General argues in the lawsuit that exceptions to the wage laws do not apply to Geo because it is a private company holding people on civil, not criminal, charges.

“Geo has a captive population of vulnerable individuals who cannot advocate for themselves and this corporation is profiting on that,” Attorney General Bob Ferguson at a press conference announcing the lawsuit.

The company said the allegations in the suit were “baseless.”

“The volunteer work program at all federal immigration facilities as well as the minimum wage rates and standards associated with the program are set exclusively by the federal government,” the company said in a statement.

ICE said it does not comment on pending litigation.

The case follows another lawsuit filed earlier this year by a group of former detainees of a Geo Group facility in Aurora, Colorado who said the work program was equivalent to forced labor.