GREAT FALLS — This is an official press release from the U.S. Department of Justice (Federal Bureau of Investigation (FBI)), published as received.

GREAT FALLS - A Brockton man accused of assaulting a man and sexually assaulting a minor on the Fort Peck Indian Reservation admitted to charges yesterday, U.S. Attorney Kurt Alme said.

The defendant, Eithan Toby McKay, 22, pleaded guilty to one count of sexual abuse of a minor and one count of assault with a dangerous weapon. McKay faces a maximum imprisonment of 15 years, a $250,000 fine and up to a lifetime of supervised release.

U.S. Magistrate Judge John T. Johnston presided. U.S. District Judge William W. Mercer will determine any sentence after considering the U.S. Sentencing Guidelines and other statutory factors. Sentencing will be set for a later date. McKay was detained pending further proceedings.

The government alleged in court documents that in September 2024, law enforcement received information about a juvenile female, Jane Doe, being pregnant. Doe was subsequently interviewed and identified Eithan Toby McKay as the father. Doe and McKay met on social media and started hanging out. The two engaged in a sexual relationship and conceived a child. Based on the due date, it was determined that Doe was 13 years old at the time of conception. McKay was 19 at the time. DNA testing later determined that Doe and McKay are 5.7 billion times more likely to be the parents than if Doe and an unrelated randomly selected person are the parents.

Additionally, shortly after 2:00 am on March 4, 2025, a person called 911 to report an assault at an address in Brockton. The person said an individual was struck over the head with a machete and was bleeding. When asked by the 911 operator if the perpetrator was still there the caller said, “He just walked in the living room - he’s drunk - it’s Eithan McKay.”

Law enforcement arrived and found the victim, John Doe, with serious injuries to his head, arm, and shoulder. Doe was bleeding heavily. The responding officer could see Doe’s bones in multiple places and applied a tourniquet. Doe said Eithan McKay slashed him with a machete because Doe wanted to leave and McKay didn’t want him to leave. As they loaded Doe into an ambulance, McKay walked over with his hands in the air and said he did it. He continued by saying he stabbed Doe and then Doe took the machete from him.

Doe was transported by ambulance to a nearby hospital with severe lacerations to the shoulder, arm, head, and back. He was provided fentanyl for pain management. He was air flighted to Billings for treatment.

Assistant U.S. Attorney Kalah Paisley prosecuted the case. The FBI and Fort Peck Tribes Department of Law and Justice conducted the investigation.

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