DERBY, Vt. -- A federal search warrant was served today in the case of a missing M16 assault rifle stolen in August from a police cruiser parked at a Vermont State Police trooper's home.

Police would not say where the warrant was served or who was involved, but did say the federal Bureau of Alcohol Tobacco and Firearms is offering a $1,500 reward in the case, which also involved the theft of a large quantity of ammunition.

The theft occurred sometime over the weekend of Aug. 9 while the cruiser was parked at the trooper's Route 105 home in Brighton, Vermont State Police said.

The thief smashed out the rear window of the cruiser and removed a gun case containing the M16 rifle and ammunition, police said.

Anyone with information regarding the theft is asked to call 802-334-8881.