St. Louis County man convicted of four sex crimes against minor

A St. Louis County judge found Shawn Francis Mortensen, 46, guilty of four sex crimes against a minor after a four-day bench trial in St. Louis County District Court, bringing a years-long case back to conviction.

Mortensen was convicted of two counts of criminal sexual conduct in the first degree for sexual contact with a child under 13, one first-degree count involving a victim under 16 with a significant relationship and multiple acts over an extended period of time, and one fifth-degree count involving sexual contact with a person under 16. The offenses occurred between February 2012 and October 2015 and involved a minor female.

The case was first filed in 2015, dismissed, and refiled in 2018, underscoring how long some child sexual abuse prosecutions can take to move through the courts. St. Louis County Attorney Kim Maki said, “We are grateful that the victim remained committed to achieving justice in this case, despite the twists and turns of the legal process,” and added that “justice delayed is not justice denied.”

The county attorney’s office said the investigation drew on the St. Louis County Sheriff’s Office, the St. Louis County Public Health and Human Services Department, and First Witness Child Advocacy Center, which provided expertise in forensic interviewing. Those agencies are part of the response network that helps local authorities investigate allegations involving children while limiting repeated interviewing of young victims.

Sentencing is scheduled for July 7, 2026. The verdict closes one chapter in a case that stretched across more than a decade from the first reported offenses to the court’s finding of guilt, with the next step now in the hands of the judge at sentencing.