FARGO, N.D. (AP) – A Belcourt woman has agreed to plead guilty for her role in a conspiracy to steal painkillers from a North Dakota American Indian hospital that was the basis of a congressional investigation.

Candace Keplin, 27, is one of four people charged in federal court with conspiracy to possess and distribute hydrocodone. Court documents show that nearly 49,000 pills were stolen from the Turtle Mountain Indian Reservation hospital in Belcourt between February 2009 and March 2010.

Documents show the drugs were stored at a residence shared by Keplin and Timothy Davis Jr. Keplin allegedly handled money that was gained from drug sales, the government said.

Davis, John Allery and Jordan Delong have pleaded not guilty in the case. They are scheduled for trial on June 6.

An investigation led by former North Dakota Sen. Byron Dorgan into regional Indian Health Services facilities highlighted problems with stolen drugs at the Quentin N. Burdick Memorial Hospital in Belcourt. Dorgan's report released two weeks ago accuses the hospital of poor oversight, auditing and staffing at the pharmacy.

The Belcourt hospital has “had a troubling history of diverted narcotics and other controlled substances,” the report said. The hospital discovered missing or stolen drugs on four separate occasions in 2010, the report said.

In a separate case, Douglas Aos has pleaded not guilty to acquisition of controlled substances by misrepresentation for drugs he allegedly obtained from the Belcourt hospital. His trial is set for April 12.

U.S. Attorney Timothy Purdon declined to comment. Prosecutors said in the plea agreement that more details should be released in Keplin's plea hearing, which has not been scheduled.

Keplin faces a maximum sentence of 10 years in prison and a $500,000 fine.

Dorgan's probe covers the Aberdeen Area of the IHS, which serves 18 tribes in North Dakota, South Dakota, Iowa and Nebraska. Besides the Belcourt hospital, the report pointed out missing or stolen drugs at the Rapid City IHS hospital and the Sisseton Service Unit, both in South Dakota.