PALMER, Alaska (KTUU) – A Wasilla man’s state plea hearing was rescheduled Thursday so he can first be federally sentenced in the death of a Wasilla teen who died of a carfentanil overdose in 2024.
Sean Doylton Mobley, 45, appeared in Palmer court as Assistant Attorney General Katholyn Runnels discussed an own recognizance bail release plan with Judge John Cagle.
Mobley faces both state and federal charges in the death of 16-year-old Alena Toennis.
Assistant Attorney General Lindsay Ingaldson explained the unusual coordination. Since both governments charged Mobley for the same conduct, federal sentencing will happen first, followed by state sentencing. The purpose is to ensure he serves his sentence in federal prison.
“The purpose of [Thursday’s] hearing was [to] make sure that Mr. Mobley is in primary federal custody,” Ingaldson said. “There was an agreement reached between both the federal government and the state [to] have charged Mr. Mobley in separate cases, but for the same conduct. In order to effectuate the agreement that we have reached with the feds, Mr. Mobley will need to do his federal sentencing first, then the state sentencing will come next so that we can ensure that he’s serving his time in a federal facility.”
Mobley initially pleaded not guilty to all state charges. That is expected to change at his rescheduled plea hearing on Feb. 5. He is scheduled to be federally sentenced on Jan. 22.
Mobley is now in federal custody but will remain in the Alaska prison system while awaiting his sentences. Alaska has no federal facility.
Mobley’s defense attorney appeared by phone at Thursday’s hearing and confirmed his client is in agreement with the custody transfer arrangement.
Ingaldson told the court that prosecutors have contacted the victim’s family and they are in agreement with the coordination plan.
Mobley was indicted federally on charges of distributing carfentanil to two individuals, resulting in the fatal overdose of a minor and the non-fatal overdose of an adult, to which he pled guilty to in October 2025.
Those federal charges consist of one count of distribution of controlled substance resulting in serious bodily injury and death, and one count of distribution of controlled substance resulting in serious bodily injury.
On the state’s side, Runnels explained that Mobley is expected to change his plea to guilty to the charge of first-degree misconduct involving a controlled substance. The original manslaughter and second-degree murder charges for the state were dropped due to the federal charges.
Additionally, in a separate federal case, Mobley is charged with felon in possession of a firearm in a separate January 2025 incident.
While Mobley has not yet pled guilty to the state charge, prosecutors said Mobley will serve 30 years on federal charges and 20 years on the state case after a guilty plea is made. The sentences will run concurrently in a federal prison outside Alaska.
Background: November 2024 overdose deaths
The sequence of events unfolded over two days in mid-November 2024, according to court documents. Mobley distributed what he believed to have been powdered fentanyl to an adult victim on Nov. 14. The man overdosed and was revived with Narcan. An associate warned Mobley not to distribute the substance to anyone else given the severity of the overdose, prosecutors say.
Despite the warning, prosecutors say Mobley continued dealing drugs that same evening, meeting Toennis at a gas station around 11:54 p.m. on Nov. 14.
Toennis texted a friend that she was “banging one out with Sean,” slang for using drugs, according to court documents. Mobley then drove her to a remote ATV trail in Wasilla, arriving around midnight, prosecutors say.
Testing showed the substance that caused both overdoses was not fentanyl as represented, but carfentanil. According to the Drug Enforcement Administration, carfentanil is a veterinary sedative used for large animals that is 100 times more potent than fentanyl and 10,000 times more potent than morphine. It is not approved for human use.
According to prosecutors, Toennis used the carfentanil while in Mobley’s truck and fatally overdosed between 12 a.m. and 12:13 a.m. on Nov. 15.
Mobley then dumped her body on the ATV trail and left to continue distributing narcotics, they say. A person walking a dog discovered Toennis’ body later that morning.
The state medical examiner determined the cause of death was acute combined toxic effects of carfentanil and methamphetamine, with hypothermia as a contributing condition.
State prosecutors said cell phone records, surveillance video, and text messages place Mobley with Toennis during her final moments alive. The evidence includes messages between them discussing illegal narcotics, Toennis’ phone movements matching Mobley’s device, and surveillance video showing his vehicle tracking her location.
The federal carfentanil distribution prosecution marks the first such case in Alaska, according to federal prosecutors. The state murder charge carries a potential life sentence as well.
Mobley has an extensive prior criminal history in Alaska, including convictions for forgery, theft, criminal trespass and misconduct involving controlled substances dating back to 2000, according to court records.
U.S. Attorney Michael J. Heyman called the case troubling in a statement released in June 2025 when federal charges were first announced.
“Mr. Mobley is accused of distributing this toxic substance to two people, resulting in the near deadly overdose of one and the heartbreaking fatal overdose of a local minor whose body he then dumped onto a secluded trail in the middle of the night,” Heyman said. “Aggressive prosecutions of individuals peddling deadly drugs to our communities, including our children, is a national priority.”