Giovanni Pamio led the team of engineers responsible for designing the defeat device, according to the DOJ.

The United States Department of Justice (DOJ) has charged a former Audi manager named Giovanni Pamio with conspiracy to cheat on emissions tests in the United States.

60-year old Pamio was head of thermodynamics within Audi's diesel engine development department from 2002 to 2015. The DOJ explains he directed his engineers to develop Volkswagen's infamous emissions defeat device when he realized designing a diesel engine that complied with U.S. emissions regulations and satisfied his employer's demands was impossible.

To legally comply with EPA and CARB regulations, the brand's diesel-powered cars would have needed to carry a large amount of AdBlue fluid on-board. Engineers feared building vehicles with a bigger AdBlue tank would prevent them from fitting more attractive features like a high-end sound system.

Consequently, the defeat device was baked into the 3.0-liter V6 TDI engine from the get-go, and it allowed the six-cylinder to satisfy emissions regulations. The V6 equipped thousands of U.S.-spec cars built between the 2009 and 2016 model years, including the Porsche Macan, the Audi Q7, and the Volkswagen Touareg.

The main defeat device consists of sensors that detect whether the car is driving on the road, or whether it's undergoing emissions testing on a dyno. It injects more AdBlue into the exhaust system when it's in testing mode to emit fewer pollutants. The DOJ points out a second defeat device disables the exhaust gas recirculation (EGR) system when the car is on the road, again resulting in higher emissions.

Some of the engineers who worked on the systems knew they were illegal. In 2008, they sent a presentation to senior Audi managers -- including Pamio -- to warn them that the software was "cycle beating." They concluded it was "highly problematic in the U.S." because it could be considered a defeat device, and it could get discovered by regulators. Later on, an employee told Pamio that the software "is a plain defeat device and it is not certifiable."

The DOJ found out about Pamio's involvement in the scandal from an anonymous witness who also worked in Audi's diesel engine development department. The person has agreed to cooperate with investigators in exchange for immunity.

The charges against Pamio include conspiracy to defraud the U.S., wire fraud, and violation of the clean air act. The DOJ stresses he has merely been charged, and he is innocent until proven guilty.