An anonymous tip alerted Mansfield Police that four Mansfield residents were planning to rob a drug dealer on Tuesday afternoon.

 Sean Boswell Jr., 20, of 101 Chilson Ave., Israel Rivera, 19, of 14 Pineneelde Ln., Cormier Hayden, 20, of 479 North Main St. and Mark Medeiros, 19, of 18 Fuller Pl. were all arrested for attempting to commit armed robbery, trespassing on residential property and conspiracy to violate drug laws.

A caller from Verrochi Inc. on County Street reported that the youths were talking about robbing someone.

The caller then reported hearing a gun cocking and then seeing the barrel of a handgun, which was recovered near the train tracks and found to be a BB gun.

Police said that the dealer ran off into the woods when they arrived.