PIERRE — This is an official press release from the U.S. Department of Justice (USAO - South Dakota), published as received.

PIERRE - United States Attorney Alison J. Ramsdell announced today that U.S. District Judge Eric C. Schulte has sentenced an Eagle Butte, South Dakota, man convicted of Failure to Register as a Sex Offender. The sentencing took place on February 3, 2025.

Arnold Dean Buck Elk Thunder, Jr., 57, was sentenced to 18 months in federal prison, followed by five years of supervised release, and ordered to pay a $100 special assessment to the Federal Crime Victims Fund.

Buck Elk Thunder was indicted for Failure to Register as a Sex Offender by a federal grand jury in September 2024. He pleaded guilty on November 7, 2024.

Buck Elk Thunder was required to register as a sex offender under the Sex Offender Registration and Notification Act as a result of a state felony conviction in May 2001 for Sexual Contact with a Child Under the Age of 16. On February 15, 2024, Buck Elk Thunder updated his registered address to a residence in Eagle Butte, on the Cheyenne River Indian Reservation. In May 2024, Buck Elk Thunder moved from his registered address in Eagle Butte to Rapid City, South Dakota, before returning to the Cheyenne River Indian Reservation and residing in Cherry Creek, South Dakota. Buck Elk Thunder knew he was required to update his registration within three business days of changing his residence but failed to do so after leaving Eagle Butte.

This case was brought as part of Project Safe Childhood, a nationwide initiative to combat the growing epidemic of child sexual exploitation and abuse, launched in 2006 by the Department of Justice. Led by the U.S. Attorneys’ Offices and DOJ’s Child Exploitation and Obscenity Section, Project Safe Childhood marshals federal, state, and local resources to locate, apprehend, and prosecute individuals who exploit children, as well as identify and rescue victims.  For more information about Project Safe Childhood, please visit https://www.justice.gov/psc.

This case was investigated by the U.S. Marshals Service. Assistant U.S. Attorney Wayne Venhuizen prosecuted the case.

Buck Elk Thunder was immediately remanded to the custody of the U.S. Marshals Service.