Prosecutors say the scheme stripped the Swiss government of more than €8 million.
Swiss prosecutors have opened a criminal case against a former federal roads office official over an alleged scam to avoid fees on carbon dioxide emissions.
The Swiss Attorney General's office claims that two board members of a vehicle import company paid the official to edit data that calculated emissions.
By making it appear as though cars did not emit as much greenhouse gas, they took around 9 million Swiss Francs (€8.15 million) from the government, prosecutors said.
The former official of the Federal Roads Office (FEDRO) and two board members have been indicted as co-conspirators.
The former official has been charged with forging documents, accepting bribes, commercial tax fraud and obtaining a false certificate by fraud. The two other suspects face charges of inciting the same offences.
Prosecutors say the official - who worked as a technical case officer for the Road Traffic Division - had received 2,000 Swiss francs in cash each month for manipulating FEDRO's computer systems.
As a result of the plot, the company avoided more than three years' worth of fees on CO2 emissions between 2014 and 2017, the attorney general's office said in a statement.
The regulations had been introduced by Swiss authorities in 2012 to reduce emissions in new cars and protect the environment.
If the average emissions of all vehicles of an importer exceed 130g CO2/km, the company is subject to a fee.
The criminal case comes after FEDRO filed a complaint in September 2017.
The three suspects, who have not been named, are presumed innocent pending the court proceedings under Swiss law.