Updated

Prosecutors have netted a string of guilty pleas among the suspects in an interstate drug trafficking case that highlighted the criminal underside of an oil boom sweeping the Northern Plains.

The latest suspect is Robert Farrell Armstrong of Moses Lake, Wash., — described by authorities as the supplier for a large methamphetamine ring in the Bakken oil patch.

He was scheduled to appear in federal court in Billings on Wednesday to plead guilty to possession of methamphetamine with intent to distribute. He faces a minimum 10 years in prison.

Armstrong was arrested in October in a crackdown aimed at offsetting rising crime in the oil producing region along the Montana-North Dakota border.

Nine others have pleaded guilty in related cases in Montana. Several cases in North Dakota remain pending.