Murder of Jessica Ridgeway

On October 5, 2012, Jessica Ridgeway, age 10, left her home in Westminster, Colorado, to walk to Witt Elementary School. When school officials later contacted her mother to report that Jessica had never arrived, her mother notified law enforcement that afternoon, triggering a 17-day search and investigation. Investigators canvassed neighborhoods and collected more than 700 DNA samples during the search.

On October 7, 2012, Jessica's backpack was found along with her glasses and clothing items that smelled of urine. According to then-Chief Deputy District Attorney Hal Sargent, these items had been placed deliberately to signal that Jessica was dead. On October 10, 2012, her torso was discovered inside two black plastic bags in Pattridge Park in Arvada, Colorado, roughly nine miles from her home. Sargent stated the remains had been placed so they would be found.

The Westminster Police Department connected Jessica's abduction to an earlier attempted kidnapping on May 28, 2012, in which a woman jogging was assaulted with a chemical-soaked rag but escaped and called 911. She described her attacker as a white or light-skinned man, aged 18–30, with brown hair, about 5 feet 8 inches tall.

The person responsible, Austin Sigg, was 17 years old at the time of the crime. Sigg, the son of a media executive, had studied mortuary science at Arapahoe Community College. According to unsealed court documents, Sigg had developed an addiction to child pornography beginning around age 12, and law enforcement found violent and sexually explicit material, including depictions of dismemberment, on his phone.

Because Sigg was a juvenile at the time of the offense, a 2005 U.S. Supreme Court decision made him ineligible for the death penalty. He was initially held at a youth detention facility and first appeared in Jefferson County juvenile court on October 25, 2012, where prosecutors announced intent to try him as an adult. On October 30, 2012, Sigg was formally charged as an adult on 17 counts, including first-degree murder, second-degree kidnapping, felony murder, robbery, attempted sexual assault, and attempted kidnapping, covering both the Ridgeway killing and the May 2012 attempted abduction.

At trial, defense counsel argued Sigg's age at the time made him unable to fully understand the severity of his actions, while prosecutors argued the crimes were meticulously planned. On October 1, 2013, Sigg pled guilty in Jefferson County District Court to 15 charges, including first-degree murder, sexual assault of a minor, kidnapping, attempted kidnapping, and sexual exploitation of a minor, against the advice of his own attorneys. He also confessed to the May 2012 attempted kidnapping. Judge Stephen Munsinger accepted the plea.

On November 19, 2013, Sigg was sentenced to life in prison, with the possibility of parole after 40 years, plus an additional 86 years to be served once parole eligibility begins. Munsinger rejected arguments that the sentence was cruel and unusual, stating the case "cries out for a life sentence." In June 2014, Sigg was transferred to an undisclosed out-of-state prison for privacy and safety reasons.