Four people, three of them teen-agers, were arrested and charged with possession of marijuana Saturday night after their car was stopped for traffic violations and a police dog signaled the presence of drugs in the vehicle.

Taneytown Police Chief Mel Diggs said Officer Edward Engel received a complaint of drugs in a car, went to the spot and saw four people enter the vehicle and drive through the city. Officer Engel reportedly followed the vehicle and stopped it after noticing several traffic violations.

Mr. Diggs said the officer walked his dog, Dany, around the vehicle, and the dog signaled the scent of drugs by sitting, barking and biting at the door handle.

The officer reported that he found two sandwich bags of suspected marijuana in the car and a third bag in the pocket of a 21-year-old man sitting in the back seat.

The man also had a white pipe containing marijuana in his belt, police said.

The bags of marijuana were valued at about $40 each, the chief said.

Bruce W. Crone of Kump Station Road was charged with possession of marijuana and possession of paraphernalia and held in lieu of $5,000 bond.

Three teen-agers, two girls and a boy, were charged as juveniles.

Chief Diggs said the 1990 Chevrolet driven by a 17-year-old girl was confiscated by police.