On Monday, the Wall Street Journal wrote that investigators from the US Department of Justice have evidence to support criminal charges against Volkswagen Group for installing illegal software on 600,000 diesel vehicles sold in the US between 2009 and 2015. The illegal software circumvented emissions regulations.

Those same sources for the WSJ say that prosecutors are torn between seeking a guilty plea from the company or negotiating a deferred prosecution agreement. The deferred prosecution agreement would dismiss charges against VW as long as the automaker signs an agreement to stick to certain settlement terms.

Reuters confirmed the situation with two sources. Reuters reported earlier this summer that a consent decree between the US and VW Group could involve “an independent monitor overseeing the German automaker's conduct and significant yet-to-be determined fines for emissions violations.”

WSJ sources say that Volkswagen is expected to receive some leniency for coming to a $15 billion civil settlement with prosecutors in June. In the settlement, VW offers to buy back affected diesel vehicles from owners at their worth before the emissions cheating scandal was made public. Still, those sources say additional fines for criminal charges could exceed the record $1.2 billion that Toyota was fined in 2014. Toyota was fined for failing to disclose acceleration issues with their cars to US authorities.

If charges are brought against Volkswagen, those charges could involve misleading regulators and consumers. According to the WSJ’s sources, prosecutors have not decided which specific charges to bring against the company.

The WSJ says that the DOJ could still bring charges against individual employees of VW Group as well, although many of them live in Germany and would need to be extradited. In July, attorneys general in Maryland, New York, and Massachusetts filed civil lawsuits naming two dozen VW Group employees as participants in the scheme to install illegal software on Volkswagen, Audi, and Porsche brand cars. The WSJ reports that a separate federal criminal probe involves “multiple individuals” from VW Group.

According to Reuters’ sources, Volkswagen is completing its own internal investigation. That investigation, as well as the various civil suits launched against the company, has “slowed progress on reaching a settlement of the criminal investigation.”

VW is also facing potential fines and legal costs pertaining to 85,000 3.0L diesel vehicles which were not covered in the $15 billion June civil settlement.