Dateline: Secrets Uncovered season 9 episode 23, 'Footprint in the Dust': A detailed case overview

Dateline: Secrets Uncovered returns to the Susan “Susie” Casey homicide in season 9, episode 23, Footprint in the Dust.

The episode covers the disappearance of a 34-year-old mother of four who worked in local health care, and vanished near her Glendive, Montana, apartment on April 12, 2008, and how investigators built a case from early scene details, phone records, and surveillance video.

This re-air on Oxygen is set for Thursday, August 21, 2025, at 11 pm. Footprint in the Dust reconstructs the apartment-door sequence, then follows the search, the Yellowstone River recovery weeks later, and the multi-year inquiry that led to charges and a verdict.

Craig Melvin from Dateline: Secrets Uncovered (Image via Oxygen)

The case file outlines three men under scrutiny, the strained divorce process, and the short walk from the drop-off point to the door. Phone activity, surveillance video, and a cleaned vehicle are presented as key evidence at trial. The episode also details the prosecution that led to a conviction in Dawson County District Court, with sentencing terms and restitution reported by local outlets.

---

Dateline: Secrets Uncovered case timeline and key facts

On April 12, 2008, Casey was dropped about 20 steps from her apartment in the early morning. Marks at the doorway suggested a struggle, and a search began. In early May, her body was recovered from the Yellowstone River. The autopsy cited strangulation, according to Independent Record.

Investigators reviewed surveillance near the complex and matched phone records to the same time window. In 2013, a jury found Walter “Marty” Larson guilty of deliberate homicide, and the court imposed a lengthy sentence.

According to KULR-8’s first-day trial report (August 20, 2013), the defense floated alternate suspects and pointed to prior domestic conflict, while prosecutors said Walter “Marty” Larson drove in the night, waited outside the building, and acted in anger after learning Casey was seeing someone new.

A bank security video placed a van linked to Larson outside the apartment before the drop-off and leaving soon after, and phone records lined up with that window, per Independent Record.

Susie Casey's Home from Dateline: Footprint in the Dust (Image via Facebook/ Dateline NBC)

---

Dateline: Secrets Uncovered investigation and verdict

Larson was arrested after a multi-year inquiry that included surveillance review, phone analysis, and a minivan search. At trial, prosecutors described a route from Billings to Glendive, the encounter outside the apartment, and the disposal in the river.

The jury found Larson guilty of deliberate homicide and felony tampering. Judge Richard Simonton imposed 100 years for the murder plus 10 years for tampering, with parole eligibility after 30 years and restitution for funeral expenses.

Prosecutors argued jealousy as the motive after learning Casey was in a relationship with Brad Holzer, while the defense pointed to alternate suspects.

Prison cell from Dateline: Secrets Uncovered (Image via YouTube/ @DatelineNBC)

---

The Dateline: Secrets Uncovered episode Footprint in the Dust re-airs on Oxygen on Thursday, August 21, 2025, at 11 pm. The series streams on NBC platforms and live TV services that carry Oxygen, including fuboTV and YouTube TV, with on-demand availability varying by provider.