Investigators today linked a shot fired at a South Side house to a series of shootings along I-270, raising the number to 16 cases.The latest case, which happened Monday, was the third to occur after the death of a Washington Court House woman on Nov. 25. The bullet -- the seventh to be linked ballistically to the shootings -- penetrated a Brown Road home and struck a bathtub. No one was injured. Franklin County Sheriff's Chief Deputy Steve Martin said a man living in the house heard three shots about 12:30 a.m. Two bullet holes were found in the front...