Fiat sites across Europe have been raided as part of an investigation into diesel emissions. Industrial offices belonging to Fiat Chrysler (FCA) and CNH Industrial were searched on Wednesday in Germany, Italy and Switzerland as part of a probe initiated by German prosecutors investigating emissions fraud. Engines used in Fiat, Alfa Romeo and Jeep vehicles, as well as in CNH Industrial's Iveco trucks, have been found to contain potentially illegal engine management software to mask excessive emissions, prosecutors said. The Frankfurt prosecutor's office stopped short of naming Alfa Romeo and Fiat's parent company, Fiat Chrysler, as under German law only individuals, not companies, can be prosecuted. The investigation is focused on nine individuals working at an "international carmaker" and seeks to establish their role in putting cars equipped with potentially illegal emissions software on public roads, the prosecutor's office said. A spokesman for FCA said that a number of the group's offices in Europe were visited by investigators in the context of a request for assistance by magistrates in Germany, and added it was co-operating fully with the authorities. In a statement CNH Industrial also confirmed authorities had visited its premises. FCA and CNH Industrial are both controlled by Exor, the holding company of Italy's Agnelli family. Potentially illegal software has been detected in the 1.3 litre and 1.6 litre Multijet engines used in Alfa Romeo, Jeep and Fiat engines as well as in commercial diesel engines used in Iveco and Fiat commercial vehicles, the prosecutors said. Although these cars passed pollution tests in a laboratory, the cars used software to largely switch off exhaust emissions filtering while driving on the road, they added. The investigation, which was co-ordinated by the EU justice agency Eurojust, focuses on nine people living in Italy and their activities from 2014 to 2019, they said. “While vehicles complied with NOx [nitrogen oxides] limits in the testing mode, the defeat devices are assumed to turn off the exhaust cleaning in real driving,” prosecutors said. “The use of such defeat devices is banned” under EU rules. Cars with such equipment cannot be approved anywhere in the bloc, and owners risk driving bans or losing permission to use them, the prosecutors said. While the car models have been certified by Italian regulators, prosecutors are not bound by that finding and can review the issue on their own. Prosecutors say more than 200,000 vehicles are affected in Germany. The raids come almost five years after a US investigation became public into Volkswagen AG over the use of so-called defeat devices in its engines. While VW and Daimler AG have settled criminal investigations, Wednesday’s raids show that authorities have not yet put the issue aside.