Jan. 27 (UPI) -- German prosecutors on Friday named former Volkswagen CEO Martin Winterkorn as a suspect in an investigation into the company's emissions cheating scandal.
Prosecutors expanded the scope of at least three investigations into elements of the Volkswagen scandal, adding 16 more names to the list of suspects, which now totals 37.
No criminal charges have been filed, but investigators continue to dive deep into the question of how millions of Volkswagen diesel vehicles became outfitted with what U.S. regulators termed "defeat devices" meant to mask the vehicle's true emissions.
Winterkorn testified to German lawmakers he only became aware of the defeat devices in September of 2015, shortly before the company admitted to U.S. regulators it had been cheating emissions standards. German prosecutors initially listed Winterkorn as a suspect, then removed his name from the list before adding it back on Friday. They have already named several top VW executives who reported directly to Winterkorn as suspects.
"Sufficient indications have resulted from the investigation, particularly the questioning of witnesses and suspects as well as the analysis of seized data, that [Winterkorn] may have known about the manipulating software and its effects sooner than he has said publicly," prosecutors said in a statement.
Winterkorn resigned his post at VW in the wake of the scandal.
Investigators completed new searches for data and communications related to the Volkswagen emissions scandal from the company, and private residences and computers of top current and former company officials.
Volkswagen has maintained the defeat devices, which are illegal in the United States, were not outlawed by the European Union, despite the fact that millions vehicles were emitting more pollution than the company claimed.
Volkswagen settled the investigation by U.S. regulators late last year, agreeing to pay a $4.3 billion criminal fine. That came after the company settled multiple civil actions for more than $17 billion. European investors are seeking an additional 9 billion euros, or $9.65 billion, in compensation after the company's stock price plunged by more than half in the days after the emissions scandal became public.