Police in Germany raided a number of offices belonging to Mercedes-Benz's parent company Daimler on Tuesday.
The raids on the 11 offices in the German states of Saxony, Lower Saxony, Berlin and Baden-Wuerttemberg were conducted as a part of investigations into possible fraudulent emissions data by company employees.
Some 230 police officers and 23 prosecutors took part in the raid. According to the New York Times, they were searching for digital and analogue documents that could be used as evidence to support the allegations.
According to the BBC, Daimler said it was co-operating with authorities, and that "known and unknown" employees were being looked into over concerns surrounding misleading advertising and fraud.
Daimler is suspected of manipulating diesel exhaust emissions, and has already said that a number of authorities in both Europe and the United States were looking into the emissions control systems that are installed in Mercedes-Benz vehicles.
To date, Volkswagen is the only manufacturer to have been found to have purposely fitted its cars with "defeat devices" in order to cheat emissions tests.
These include Renault, PSA Group – the parent company of Peugeot, Citroen and DS Automobiles – and Fiat Chrysler Automobiles. According to the BBC, authorities in the United States are planning on launching legal action against FCA in the next few days.
Volkswagen pleaded guilty to three charges concerning emissions cheating earlier this year as a part of a deal with US prosecutors.
The manufacturer has had to set aside a staggering £19 billion for compensation and fines.