Persuaded to be in the presence of a vast traffic of stolen vehicles, the Yvelines police officers then embark on a meticulous work of telephone exploitation. For example, the telephone lines of two Renault-Flins employees, one of whom is a coachbuilder, are identified. The DNA found in the vehicles makes it possible to confuse them and make a formal link between the thefts at Peugeot and Renault. One of the criminals is already known to the police: he was arrested in March 2018 in Le Havre driving the another vehicle falsely registered and stolen from the Poissy factory. All these elements are put end to end. A special investigation group has been set up, bringing together police officers from Conflans-Sainte-Honorine police station, Yvelines departmental security and the regional intervention group (GIR). Telephone tapping, technical surveillance and spinning then confirm the existence of an association of experienced criminals. "They stole new vehicles in the Yvelines before shipping them to Le Havre for their likely export abroad," said a police source.