FRESNO, Calif. (KSEE/KGPE) – The Homeland Security Investigations office in Fresno was part of the investigation of an Oklahoma man sentenced on Monday for advertising and distributing child sexual abuse material, the United States Department of Justice said.

According to court documents, between March 2018 and August 2019, 36-year-old Austen Peppers of Oklahoma sold and offered to sell images of minors being sexually abused. He conducted transactions on the dark web with cryptocurrency, using platforms and applications that he believed were secure and protected him from law enforcement scrutiny.

The DOJ says Peppers also engaged in sexually explicit communications with persons he believed to be minors and couraged those apparent minors to create sexually explicit images of themselves. He amassed thousands of images and videos of children being sexually abused.

This case was the product of an investigation by the Homeland Security Investigations officers in Fresno, Chicago, and Oklahoma.

The DOJ says Peppers was sentenced to 21 years and 10 months in prison to be followed by 15 years of supervised release. He has been in custody since his initial appearance in this case on Nov. 14, 2019.