A pair of men police blame for a rash of smash 'n' grab robberies in the Chinatown/North Beach area were arrested early this morning by plainclothes officers. Nicknamed the "River Rock Burglar" because of his continued use of smooth, cobblestone-like rocks to smash store windows, the alleged thieves are accused of at least seven burglaries since early July. Police suspected a man who had been convicted of at least 13 similar "river rock burglaries" during two separate crime sprees over the
