Volkswagen: No serious violations by executives

Preliminary results of an internal investigation into Volkswagen Group's emissions scandal have revealed no serious violations by past or present top executives, the company said Wednesday.

The German automaker's board said in a statement that although the investigation is not yet complete, an internal probe has uncovered no "serious and manifest breaches of duty on the part of any serving or former" top executives.

The company reiterated that it would not disclose details of the internal investigation until at least late 2016. VW fears that releasing details would disrupt the criminal investigation ongoing at the U.S. Justice Department.

U.S. law firm Jones Day has been conducting an investigation of VW's emissions scandal at the behest of the company, which installed software on some 11 million diesel vehicles worldwide to evade emissions standards. The company recently pegged the cost of the scandal at more than $18 billion.

Law firm Gleiss Lutz conducted a "comprehensive legal review" of Jones Day's findings and, together with retired a German federal judge, concluded that VW executives were not responsible for serious violations "according to information currently available," Volkswagen said.

The automaker's leaders have previously blamed "rogue" engineers for installing the software.

Follow USA TODAY reporter Nathan Bomey on Twitter @NathanBomey.