Complex sentence: Analysis of the wreckage of the Mercedes revealed it had glancing contact with a white Fiat Uno car which left traces of paint on the Mercedes bodywork but extensive attempts by the French police to find the vehicle involved were unsuccessful.
Split into simpler sentences: Analysis of the wreckage of the Mercedes revealed it had glancing contact with a white Fiat Uno car which left traces of paint on the Mercedes bodywork. Extensive attempts by the French police to find the vehicle involved were unsuccessful.