The first of 10 defendants pleaded guilty in Natrona County District Court on Friday to his role in a multistate prescription drug conspiracy allegedly orchestrated by a Casper doctor and his wife.

During a change of plea hearing, Dustin Big Medicine pleaded guilty to one count of conspiracy to distribute oxycontin, a Schedule II drug.

In exchange for the plea, District Attorney Mike Blonigen said the state would ask for the dismissal of a second count of conspiracy to distribute the anti-anxiety drug alprazolam, the generic name for Xanax, a Schedule IV drug. The state also would ask for a suspended four- to eight-year prison sentence and probation, Blonigen said.

Judge Daniel Forgey said he accepted the plea. A judge is not bound by a plea agreement. Forgey also ordered a presentence investigation and will set a sentencing date.

Several other defendants are scheduled to make plea changes next week.

Defendants are charged with one, some or all of four counts: conspiracy to deliver a Schedule II controlled substance (oxycodone and oxycontin); conspiracy to deliver a Schedule IV controlled substance -- alprazolam; and two counts of conspiracy to deliver heroin.

Local, state and federal agencies discovered Big Medicine and the other defendants during the investigation of Dr. Shakeel Kahn and his wife, Lyn, who are charged in federal court with multiple counts, according to court records. Two other defendants were later charged in the federal drug conspiracy case: Paul Beland, and Kahn's brother Nabeel Khan.

An agent with the Wyoming Division of Criminal Investigation wrote in an affidavit that the U.S. Drug Enforcement Administration began investigating Kahn in May 2016. They had received reports he was prescribing abnormally excessive amounts of controlled substances, mostly opiates, in Natrona County. The DEA found people would travel from Fremont County and as far away as Massachusetts to obtain prescriptions.

The Kahns were arrested at their home in Casper on Nov. 30.

As the DEA's investigation progressed, the DCI learned from a patient of Kahn that people would pay $500 in cash a month for whatever they wanted, as long as they signed a contract stating they were not wearing a wire, not working with law enforcement, and promising to never call the doctor a drug dealer.

The patient added Kahn would fax the prescriptions for patients to Vape World, 211 E. 12th St., which was operated by his stepchildren. The store is now closed.

The DCI monitored conversations between Lyn Kahn and Deni Antelope, whose husband is Big Medicine, who obtained prescriptions for opiates they would sell on the Wind River Indian Reservation.

Five other defendants named in the criminal information document have yet to be bound over for trial.