Bomb suspect arrested — Suspected Upton bomb maker released on $10K bond
David Charles Riggle, born 1985, was arrested on Dec. 11 and had his first appearance in Circuit Court of the 6th Judicial District on Dec. 13. Riggle is charged with possession, manufacture, transportation and sale of explosives, improvised explosive device or incendiary apparatus with unlawful intent prohibited, a felony under Wyoming law.
Judge Lynda Bush imposed a $10,000 cash-only bond, which Riggle paid the same day.
Court documents state that, on or about Nov. 30, Riggle did possess or manufacture an explosive, improvised explosive device or incendiary apparatus with the intent to cause injury or damage to the property of another. The device, according to the affidavit of probable cause, was found shortly after 8 a.m. in a shop/storage trailer at the TYVO Drilling yard, located one mile south of Upton on Wyoming Highway 116.
When the call came into dispatch, Deputy Jared Engle responded and met with Keith Materi, the owner of TYVO Drilling yard. During talks with Materi, Engle learned that Robert Finn and Les Dixon had located the device after smelling propane when they arrived at the yard.
“Robert went inside the trailer and walked up to the 100-pound propane bottle that was secured in the front compartment next to the north wall (of the shop/storage trailer). Robert noticed the valve was turned open, and as he was turning the valve off, he looked down and saw the ignition device located to the left of the 100-pound propane tank,” the affidavit says.
Engle accompanied Materi to look at the device, and observed the 100-pound propane tank secured by a chain. Next to the propane bottle was a 6-volt battery made by ELECTRYX with two wires coming from it and connected to an egg timer, lots of wire and what appeared to be a firework fuse.
“When the egg timer hit zero it would connect the two ends of the wire that have been soldered,” the affidavit says.
After seeing the device, Engle says in the affidavit that he returned to his vehicle to wait for the Campbell County Sheriff’s Office bomb squad to arrive.
Once the bomb squad arrived, the affidavit states that upon examination, it appeared that the battery itself got hot but that there was no evidence of any heat on the end of the wires or the small piece of fuse. It notes that no other devices were located on-site.
Pictures were then taken of the device and evidence was bagged.
The affidavit states that Sgt. Travis Garhart examined the evidence, and was able to locate the same battery used in the bomb at Bomgaars in Newcastle.
According to the affidavit, the Weston County Sheriff’s Office then examined the store’s video surveillance footage to pinpoint Riggle’s identity, leading to his arrest.
“On Dec. 3, 2024, SGT Garhart and I (Engle) viewed the security tape when the ELECTRYX 6-volt battery was sold. Only one sale of the battery was made …,” the affidavit says. “The security tape was not high definition, you could tell the person was wearing a sweatshirt with a logo on the left front chest area and had another logo going down the left arm of the sweatshirt.”
Engle then checked video footage from gas stations in Newcastle, where he located the same individual entering the Maverik convenience store, and when the deputy checked the outside camera he could see the suspect pull up to a gas pump in a Suzuki SUV.
Engle then reported what he found to Weston County Sheriff Bryan Colvard, Undersheriff Dan Fields and Garhart. He noted in the affidavit that he was unable to clearly see the license plate number because of dirt and the inability of the security camera to zoom in enough.
However, the following day, while waiting for federal Alcohol, Tobacco and Firearms officials to arrive, Colvard observed the suspect’s vehicle passing the airport heading toward Newcastle. The affidavit states that Colvard radioed Garhart who was able to get a read on the plate number. The vehicle belonged to Riggle, who lives on Nester Road in Upton.
Engle states that the ATF was notified of the suspect and that Garhart was “keeping eyes” on Riggle in an unmarked vehicle.
ATF agent Brett Claflin accompanied deputies to the TYVO Drilling yard, while Garhart continued to watch Riggle. At this time, Claflin located footprints at the yard, across the perimeter fence and they sought the assistance of another local resource.
“I (Engle) contacted Lynn Busskohl with Weston County Search and Rescue; Lynn is an apprentice-level man tracker through the Joel Hardin Professional Tracking Services,” the affidavit says. “Lynn was able to find the tracks and followed them to the northeast. The tracks were headed back to Nester County Rd.”
Claflin then felt there was enough evidence to get a search warrant for Riggle’s residence.
To check for more tracks, Busskohl arranged to have two others, Brian Zerbe and Terry Browder, come up and see what they could find outside of Riggle’s home.
On Dec. 6, Busskohl, Zerbe and Browder went to the TYVO Drilling yard where they located two boot tracks inside the shop/storage trailer that matched the boot tracks going across the field. Those tracks were followed east until they had to stop for safety reasons.
“If they had gone any farther, they would have been in view of the Riggle house located on Nester County Rd.,” the affidavit says, noting that Engle contacted Claflin to share the findings as he had returned to Cheyenne to work on search warrants.
On Dec. 11, the ATF conducted the search warrants while the Weston County Sheriff’s Office placed Riggle in investigative detention.
While being interviewed by Claflin, Riggle said, without being asked, that “his phone quit working, so he was using an egg timer in the shed to know how long he had been working and someone stole the egg timer.”
During a search of Riggle’s bedroom, the ATF search warrant team found the other ELECTRYX 60 volt battery sold in a two pack along with the receipt from the purchase at Bomgaars.
They also located a hobby fuse that was the same as that used in the device, along with electrical wire that was the same used to connect the battery to the fuse and the egg timer.
Investigators also found boot prints in the bar that are an exact match to those found in the shop/storage trailer and in the field between TYVO Drilling yard and Riggle’s home.
The affidavit notes that, upon conclusion of the search, Claflin said he was going to return to Cheyenne to work on a federal warrant/hold for Riggle and that the Weston County Sheriff’s Office decided to arrest Riggle for being in violation of Wyoming State Statute 6-3-111(c).
The statute states that “any person who possesses, manufactures, transports, sells or delivers to another person any explosive, improvised explosive device, or incendiary apparatus, with the intent to cause injury or damage to the property of another as defined in W.S. 6-3-103(c), or with the intent to assist another person to do the same, is guilty of a felony. Upon conviction, he shall be punished by imprisonment for not more than five (5) years, a fine of not more than five thousand dollars ($5,000.00), or both.”
Riggle’s initial appearance was on Dec. 13, at which time Bush imposed a $10,000 cash-only bond. According to documents, he was released later that day.
Riggle is required to wear a GPS monitoring system as part of his release. Per the order setting bail, he can move freely throughout Crook, Campbell and Weston counties without informing the court.
A preliminary hearing is scheduled before Judge Bush in circuit court on Dec. 18 at 2 p.m.