Alison J. Ramsdell U.S. Attorney | U.S. Attorney for the District of South Dakota
Alison J. Ramsdell U.S. Attorney | U.S. Attorney for the District of South Dakota
A Pierre, South Dakota man has been sentenced for failing to register as a sex offender, according to an announcement from U.S. Attorney Alison J. Ramsdell. U.S. District Judge Eric C. Schulte sentenced Archie Mack, 41, on September 3, 2025.
Mack received a sentence of three months in federal prison, followed by five years of supervised release. He was also ordered to pay a $100 special assessment to the Federal Crime Victims Fund.
Mack was indicted by a federal grand jury in January 2025 and pleaded guilty on June 4, 2025.
He had previously been convicted of Sexual Abuse of a Minor in December 2005. This conviction requires him to register as a sex offender and update his registration within three business days if he relocates or changes employment or student status. In August 2024, Mack updated his registration to reflect that he was living at a residence in Pierre. However, after relocating to another residence in Pierre in September 2024, he did not update his registration as required. Authorities arrested Mack on November 19, 2024.
The case is part of Project Safe Childhood, an initiative launched by the Department of Justice in May 2006 aimed at combating child sexual exploitation and abuse. The project is led by U.S. Attorney’s Offices and the DOJ’s Child Exploitation and Obscenity Section and focuses on prosecuting individuals who exploit children while also working to identify and rescue victims. More information about Project Safe Childhood can be found at https://www.justice.gov/psc.
The investigation was conducted by the U.S. Marshals Service and the Pierre Police Department. Assistant U.S. Attorney Kirk Albertson prosecuted the case.
Mack was immediately remanded into custody following sentencing.
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