Porcupine Man Sentenced to 12 Years in Federal Prison for the Shooting Death of Pregnant Girlfriend

RAPID CITY - United States Attorney Alison J. Ramsdell announced today that U.S. District Judge Karen E. Schreier has sentenced a Porcupine, South Dakota, man convicted of Involuntary Manslaughter, the Unborn Victims of Violence Act, and Possession of an Unregistered Firearm. The sentencing took place on April 25, 2025.

McKenzie Big Crow, age 20, was sentenced to a total of 12 years in federal prison for Involuntary Manslaughter, the Unborn Victims of Violence Act, and Possession of an Unregistered Firearm, to be followed by three years of supervised release. Big Crow was also ordered to pay $300 in special assessments to the Federal Crime Victims Fund.

A federal grand jury indicted Big Crow in June 2024. In January 2025, he was found guilty following a federal jury trial.

On August 20, 2023, near Porcupine, Big Crow was illegally in possession of a Savage Arms Model 62, semiautomatic rifle. The barrel had been sawed off, and the defendant had taped components of an Airsoft rifle to the gun to make it appear like an AK-47. Big Crow claimed he put the rifle in a backpack and that the gun discharged when he bumped the bag against a door. The gunshot struck 19-year-old Ashton Provost in the chest, killing her and her unborn child within minutes. The gun was later found hidden under Big Crow’s bed. On the day of the shooting, Big Crow had drugs in his system including marijuana, cocaine, MDMA (commonly known as ecstasy) and methamphetamine.

“We commend the U.S. Attorney’s Office in the District of South Dakota for its decision to pursue charges under the Unborn Victims of Violence Act — recognizing the value of every life lost as a result of this crime,” said Special Agent in Charge Alvin M. Winston Sr. of the FBI Minneapolis. “This case highlights our shared commitment to justice for the most vulnerable and to holding violent offenders accountable to the fullest extent of the law.”

This case is part of Project Safe Neighborhoods (PSN), a program bringing together all levels of law enforcement and the communities they serve to reduce violent crime and gun violence, and to make our neighborhoods safer for everyone. On May 26, 2021, the Department launched a violent crime reduction strategy strengthening PSN based on these core principles: fostering trust and legitimacy in our communities, supporting community-based organizations that help prevent violence from occurring in the first place, setting focused and strategic enforcement priorities, and measuring the results.

This matter was prosecuted by the U.S. Attorney’s Office because the Major Crimes Act, a federal statute, mandates that certain violent crimes alleged to have occurred in Indian country be prosecuted in Federal court as opposed to State court.

This case was investigated by the FBI, the Oglala Sioux Tribe Department of Public Safety, and the Bureau of Alcohol, Tobacco, Firearms and Explosives. Assistant U.S. Attorney Heather Knox prosecuted the case.

Big Crow was immediately remanded to the custody of the U.S. Marshals Service.

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