Earlier this week, the FBI arrested a Volkswagen executive in connection with the Dieselgate scandal. Yesterday, Volkswagen reached a $4.3 billion settlement with US regulators stemming from its use of secret software to fool emissions tests. Today the Environmental Protection Agency has opened a new chapter in this sage, accusing Fiat Chrysler of using secret software to accomplish the same trick.

Cynthia Giles, an assistant administrator at the EPA, said that the software prevented emissions of nitrous oxides when it senses testing conditions, and that the level of these chemicals emitted during ordinary driving was high enough to ensure “this is a clear and serious violation of the Clean Air Act. There is no doubt that they are contributing to illegal pollution.”

The EPA stopped short of calling the software “defeat devices,” but has sent a request to Fiat Chrysler asking them to prove otherwise. The vehicles in question include Jeep Grand Cherokees from 2014 to 2016, and Dodge Ram 1500 Trucks. According to the EPA, the new charges stem from the fact that it added additional measures to its emissions testing after the revelations of Dieselgate.