Police in Manchester caught a robbery suspect by following a trail of beer cans he dropped while fleeing from the scene. Police told WMUR-TV that when Peter Mackey, 24, tried to buy a 30-pack early Saturday, a convenience store clerk told him beer cannot be sold after midnight. Mackey allegedly took out a knife, grabbed cash from the register, and fled. Police followed the cans that fell as he ran away. He was charged with armed robbery and resisting arrest.