Discover behind the scenes of the technical and scientific police (PTS)! With the series The Experts in the 2000s, the PTS was propelled to the media stage. His professions arouse curiosity and fascination even if for the general public, these professional realities remain an enigma! Armed with their briefcases with specialized tools, the PTS technicians work to make crime scenes talk and actively participate in the manifestation of the truth. Today, new methods make it possible to better treat traces and clues. In order to better understand the current PTS, this conference, conducted by a former crime scene technician with the Judicial identity of Paris, highlights the great men of the history of the scientific police and its evolution.