Madison police arrested a student at Madison Junior High School on Monday after he was found to be in possession of marijuana.

Chief Dan Thurston said a janitor at the school saw what he thought was a drug transaction. The janitor told an administrator, who followed the students into a restroom, Thurston said.

Marijuana was found on one of the students while the other did not have any contraband on him or in his locker, police said.

Police arrested a male juvenile, 12, of Madison on a charge of possession of marijuana.