Frankfurt - German police have detained four American teenagers suspected of killing two motorists by throwing stones on to a motorway from a pedestrian overpass.
Prosecutors have requested that the four, aged between 14 and 18, be placed under investigative custody. One of the suspects has admitted taking part, a spokesman said.
Two women, aged 20 and 41, driving separate cars were killed after the football-sized stones smashed their windows and sent the cars spinning out of control, prosecutors said.