The company said it is "fully cooperating with all government agencies.”
Oliver Schmidt, who oversaw the automaker's regulatory compliance office, faces fraud charges.
The automaker already agreed to pay $15.3 billion over its emissions scandal.
The settlement would be the largest ever automotive buyback offer in U.S. history and most expensive auto industry scandal.
The cars used sophisticated software to evade U.S. emission rules.
"This case has ingredients I've spent my life working on."
The bill would raise the bar for plaintiffs to join a class action, requiring each of them to have "suffered the same type and scope of injury."
The Justice Department and the Environmental Protection Agency on Monday filed a civil complaint against the German automaker in U.S. District Court in Detroit.
"Cure the air, not the cars."
"Our emissions testing will in future be verified by internal and external third parties."