PAU, France, July 15 (Reuters) - French prosecutors have opened a preliminary investigation into doping allegations against Tour de France cycling team Bahrain Victorious. The prosecutor"s office in the southern port city of Marseille said that the investigation was into "acquisition, transport, possession, import of a prohibited substance or prohibited method for use by an athlete without medical justification." The team"s accommodation and bus were searched by police after Wednesday"s 17th stage. Bahrain Victorious earlier confirmed the police search.