Local charges dropped — Upton explosives case moved to U.S. District Court
Weston County will not be forced to assume the cost of a trial for a man arrested for allegedly building and planting an explosive device at an oil field servicing business near Upton, because the accused has now been charged in federal court for the crime.
The U.S. Attorney’s Office has charged David Charles Riggle, of Upton, in relation to the discovery of an incendiary device, according to Weston County Attorney Michael Stulken, who confirmed that state charges against Riggle, born 1985, were dismissed on April 30.
Riggle was arrested on Dec. 11 by the Weston County Sheriff’s Office and originally charged with the possession, manufacture, transportation and sale of explosives, improvised explosive device or incendiary apparatus with unlawful intent prohibited, a felony under Wyoming law. The charges were related to an incident involving a propane tank bomb at Tyvo Drilling yard in Upton.
“Yes, the Weston County Attorney’s Office did dismiss Mr. Riggle’s charges without prejudice. The reasoning is that the United States Attorney’s Office for the District of Wyoming pursued the matter separate and apart from ours,” Stulken told the News Letter Journal in an email on May 5.
According to the criminal complaint filed on April 23 in the U.S. District Court for the District of Wyoming, “from on or about November 29, 2024, through and including, on or about November 30, 2024, in the District of Wyoming, the Defendant, David Riggle, maliciously attempted to damage and destroy, by means of fire and explosive materials, real or personal property located at coordinates 44.089, -104.62907, which was used in interstate commerce.” The document notes that this act is in violation of 18 United States Code Section 844(i).
The complaint then includes a sworn statement from Special Agent Brett Claflin with the Bureau of Alcohol, Tobacco, Firearms & Explosives. In the statement, he recounted the events leading to Riggle’s arrest on state charges.
According to the document, on Nov. 30, the Weston County Sheriff’s Office was dispatched to the Tyvo Drilling yard after a report of a suspicious device located in a semi-truck trailer on the north side of the property. Once on scene, Deputy Jared Engle spoke with Keith Materi, Tyvo’s production manager at the time, who said that Robert Finn smelled propane while near the trailer and when he looked inside he saw the device, which included an Electryx 6-volt battery that would eventually lead to Riggle’s arrest.
During the investigation into the origin of the device, deputies used the battery to pinpoint Bomgaars department store as a possible sale location. The actual sale of the battery was caught on surveillance video, which led investigators to another local business and eventually enabled them to identify Riggle’s vehicle.
While posted near the Upton airport that same day, Engle observed the suspect vehicle “drive down Nester Road and turn into a residence with a green roof and white exterior walls.”
The report notes the home was listed as belonging to Tom, Karen and David Riggle, and was less than a mile from the crime scene.
“The listed address is approximately 0.68 miles, across an open field, from the Tyvo lay yard where the device was recovered,” the document says.
On Dec. 4, Claflin visited the lay yard, noting footprints “stepping over a low point in the fence.”
Claflin followed the footprints east, in the direction of Riggle’s listed residence, the document states. The special agent then utilized the services of Lynn Busskohl with Weston County Sheriff’s Office Search and Rescue to follow the tracks.
“Busskohl has attended several trainings related to tracking impressions left on a surface and how different factors, such as running versus walking, affect an impression left behind,” the document states. “Busskohl arrived on scene and tracked the footprints farther east.”
When inspecting the area around the trailer where the explosive device was planted, the tracker noted that the prints “appeared to come from the east of the trailer on the property, and then the same footprints went back towards the east.”
“The footprints going east away from the trailer towards 97 Nester Road and appeared to have more of a toe impression, which Busskohl believed that meant the individual may have been moving quicker going away from the crime scene to the east,” the document states. “A mold of the footprint was taken and tagged into evidence for later comparison.
Those prints would later be linked to Riggle when a federal search warrant was executed on Dec. 11.
“There were footprints found in the garage, which had a dirt floor, that matched the description of the footprints that were discovered at the crime scene on December 4 and 6, 2024,” the document states.
Additionally, the search resulted in the discovery of an additional 6-volt Electryx battery and three packages of safety fuse.
“There were black wires, soldering equipment, and wire cutters that were also seized during the search warrant,” the document states. “The seized 6-volt battery, safety fuse, black wires, and solder matched the description of components from the recovered device.”
At this point, Claflin conducted a Mirandized interview with Riggle and later that evening he was arrested on state charges.
A second interview was conducted on Dec. 13 by Engle and Sgt. Travis Garhart upon Riggle’s request. During this interview, the documents state that Riggle admitted to going to the yard.
Claflin concluded that based on his training and experience, and the facts, there was probable cause to believe that Riggle violated the law by attempting malicious destruction of property used in interstate commerce.
A detention hearing for Riggle was held on May 2. At this time, U.S. Magistrate Judge R. Michael Shickich set a $10,000 unsecured bond. Conditions of Riggle’s release included reporting to the U.S. Probation Office as directed, residing at 97 Nester Road in Upton unless otherwise approved, and not traveling outside of the state without permission. There were other stipulations as well, including not breaking the law or possessing narcotics.