Bomb sentencing — Riggle to serve 30 months
An Upton man charged with planting a propane-based explosive device at an oilfield storage yard near Upton was sentenced to federal prison last week, bringing an end to a case that began with the discovery of the device in late 2024.
David Riggle, 40, was sentenced Jan. 27 by U.S. District Court Judge Alan B. Johnson to 30 months’ imprisonment, followed by two years of supervised release, according to the U.S. Attorney’s Office for the District of Wyoming. The court also imposed a $300 fine.
“This was not a harmless or symbolic act. The defendant placed a functioning propane-based explosive inside a work trailer, putting employees, nearby residents, and an entire community at risk of serious injury or death,” U.S. Attorney Darin Smith said in the release. “While the device failed to ignite, the fear and disruption it caused were real — employees were afraid to return to work, business operations were delayed, and a sense of safety in Upton was shaken. The law does not measure harm only by what detonates, but by the danger created and the lives put in jeopardy.”
Riggle pleaded guilty in November after waiving indictment on a federal charge of possessing a destructive device.
Federal prosecutors said the sentence reflects the seriousness of the offense, even though the device failed to ignite.
As previously reported by the News Letter Journal, the case stems from an incident discovered on the morning of Nov. 30, 2024, when workers at an oilfield supply yard near Upton smelled propane coming from a storage trailer and found an improvised explosive device inside.
Investigators later determined the device consisted of an open 100-pound propane tank positioned next to a battery-powered ignition system that included wiring, a timer and a fuse. Authorities believe the timer was intended to delay ignition so the person who placed the device could leave the area before it activated.
Although the device did not detonate, law enforcement officials said it was capable of causing serious harm.
Riggle was initially arrested on state charges on Dec. 11, 2024, following an investigation by the Weston County Sheriff’s Office, with assistance from state and federal agencies.
According to the release, the other agencies involved include the Campbell County Sheriff’s Office, Wyoming Highway Patrol and the Bureau of Alcohol, Tobacco, Firearms and Explosives.
Weston County deputies used surveillance footage, tracking evidence and materials recovered during a search of Riggle’s residence to link him to the device, according to court documents and prior reporting.
State charges were later dismissed after the case was adopted by federal prosecutors. Riggle was formally charged in U.S. District Court in April 2025 with attempting to damage or destroy property used in interstate commerce by means of fire or explosive materials. Assistant U.S. Attorney Paige Hammer prosecuted the case.
Riggle will serve his sentence in federal custody, followed by supervised release under conditions set by the court.