A German Volkswagen executive who has been in a Michigan jail for months plans to plead guilty in the company's U.S. emissions scandal, a court spokesman said Tuesday.

Oliver Schmidt, former manager of a VW engineering office in suburban Detroit, will appear in federal court on Aug. 4. His lawyers disclosed the plan during a brief conference with a judge, spokesman David Ashenfelter said.

Schmidt is one of many VW employees charged in a scheme to cheat emission rules on nearly 600,000 diesel vehicles, but most are in Germany and out of reach of U.S. authorities. He's been in custody since January when he was arrested while on vacation in Miami before he could return to Germany.

VW admits using software to get around diesel emission standards. Schmidt is charged with conspiracy and fraud. He's accused of lying to U.S. regulators by saying technical problems — not sneaky software — were to blame for the difference in emissions in road and lab tests.

A message seeking comment was left for Schmidt's lawyer.

"I'm unable to comment on what the terms of the plea agreement might be," said Gina Balaya, a spokeswoman for prosecutors.

VW pleaded guilty in March and agreed to pay $4.3 billion in criminal and civil penalties, on top of billions more to buy back cars. U.S. District Judge Sean Cox has refused to release Schmidt on bond, saying he might flee.

— The Associated Press