At least four tons of fertilizer was stolen over the weekend in Frederick, city police said. No motive had been determined.
A ton of urea and three tons of other fertilizer were taken from the Southern States store on South Street between Saturday night and Sunday morning, police said.
According to police, the fertilizer was contained for the most part in white 50-pound bags with a company logo.
Fertilizer thefts have attracted increased attention from law enforcement officials in recent years because some types of fertilizer can be used in making explosives. It was not immediately clear whether the materials taken could be used for such a purpose.
Lt. Clark Pennington said police have notified the FBI. As a matter of routine, a report of the theft was sent to a state coordinating center, which is to notify all interested federal agencies. He said detectives would work closely with those agencies in the inquiry, which was in its early stages.