<sod >Detectives believe the teenager was hit by a shotgun pellet intended for another target metres away in Harrow, where a 15-year-old was shot in the head at around the same time.< eod>< sod > Detectives believe the teenager was struck by a shotgun pellet intended for a target metres away in Harrow, where a 15-year-old was shot in the head at around the same time on Sunday afternoon.< eod>