Sioux Falls Man Sentenced to 10 Years in Federal Prison for Attempted Enticement of a Minor

SIOUX FALLS - United States Attorney Alison J. Ramsdell announced today that U.S. District Judge Roberto A. Lange has sentenced a Sioux Falls, South Dakota, man convicted of Attempted Enticement of a Minor. The sentencing took place on June 23, 2025.

William Danery Sebastian, age 34, was sentenced to 10 years in federal prison with five years of supervised release and ordered to pay a special assessment to the Federal Crime Victims Fund in the amount of $100. Sebastian must also register as a sex offender upon release from federal prison.

Sebastian was indicted by a federal grand jury in April 2024. He pleaded guilty on March 27, 2025.

The conviction stemmed from an undercover chat operation in March 2024, when Sebastian started a conversation with a person he thought was a 15-year-old female on Facebook. The conversation turned sexual in nature and Sebastian asked the 15-year-old to meet up to have a sexual encounter. Sebastian arrived at the meet location where he was arrested by law enforcement. Unbeknownst to Sebastian, he had actually been chatting with an undercover law enforcement officer posing as a 15-year-old female.

This case was investigated by Homeland Security Investigations, the Lincoln County Sheriff’s Department, and the South Dakota Internet Crimes Against Children Task Force and Human Trafficking Task Force. Assistant U.S. Attorney Elizabeth A. Ebert-Webb prosecuted the case.

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 May 2006 by the Department of Justice. Led by the U.S. Attorneys’ Offices and the 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.

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