A 36-year-old Tillamook County man was sentenced to 15 months in federal prison after pleading guilty to transporting explosives in a car, the U.S. Attorney’s Office for the District of Oregon said Tuesday.

On April 27, 2021, Cornelius police officers pulled Robert David Larsen over while he was driving a stolen car, the attorney’s office said.

Upon searching the vehicle, officers said they found explosive materials and several catalytic converters in the trunk.

They said explosive material was inside an eight-inch metal bottle filled with a smokeless, explosive powder. There was also a detonation cord inserted through a hole drilled into the bottle’s cap.

On June 1, 2021, a federal grand jury indicted Larsen on charges of possessing an unregistered destructive device, unlawfully transporting explosive materials, and possessing explosive materials as a convicted felon. On May 23, 2022, he pleaded guilty to unlawfully transporting explosive materials.

The attorney’s office said Larsen’s federal sentence will run consecutive to the time he was in state custody, which was from April 2021 to July 2022 and will be on three years of supervised release.