The Savannah-Chatham police department arrested a 15-year-old boy for armed robbery at 3:15 p.m. Wednesday near the Truman Parkway overpass at Bee Road and East Anderson Street.The suspect, armed with a handgun, reportedly robbed a 17-year-old male who was on his way home from school, said Sonny Cohrs, spokesman for Savannah-Chatham police.