SIDNEY – Authorities who discovered an assault rifle and the makings of a pipe bomb in a vehicle are trying to determine what the motorist was planning.

Trooper David Pelletier made the discovery of the weapons and cocaine Tuesday after stopping to investigate a sport utility vehicle that had remained for an extended period in a park-and-ride lot, said Stephen McCausland, spokesman for the Maine Department of Public Safety.

Seized from the SUV were the makings of a pipe bomb, a loaded AK-47 assault rifle, a shotgun, two handguns and almost a pound of cocaine, McCausland said.

Roy Garland, 20, of Waterville, was arrested after he attempted to flee, the spokesman said. He was charged with possession of explosives, aggravated trafficking in cocaine, having a loaded firearm in a vehicle, attempted escape and failing to submit to an arrest.

Investigators searched his apartment Tuesday night. Assisting state troopers were local police, state drug investigators, the fire marshal’s office and federal agencies.