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Press Release

Belle Fourche Man Sentenced to Federal Prison for Possession of Child Pornography

For Immediate Release
U.S. Attorney's Office, District of South Dakota

Acting United States Attorney Dennis R. Holmes announced that a Belle Fourche, South Dakota, man convicted of Possession of Child Pornography with a Prior Child Pornography Conviction was sentenced on April 15, 2021, by Judge Jeffrey L. Viken, U.S. District Court.

Karl Koster, age 39, was sentenced to 10 years in federal prison, followed by 5 years of supervised release, and ordered to pay a $100 special assessment to the Federal Crime Victims Fund.  Koster will also be required to register as a sex offender under the Sex Offender Registration and Notification Act.

The conviction stems from South Dakota Internet Crimes Against Children Task Force receiving two Cybertips from the National Center of Missing and Exploited Children identifying the suspect user as Koster.  Koster was previously convicted in Pennington County, South Dakota, for Make/Sale/Possess Child Pornography and was on parole at the time of his arrest.  Forensic examination of Koster’s devices revealed multiple images of child pornography, age-difficult images and internet searches associated with obtaining child pornography.

The investigation was conducted by the South Dakota Department of Corrections, South Dakota Division of Criminal Investigation, Department of Homeland Security, Rapid City Police Department, and the Pennington County Sheriff’s office.  Assistant U.S. Attorney Sarah B. Collins prosecuted the case.

Koster was remanded to the custody of the U.S. Marshals Service.

Updated April 28, 2021

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