PONTIAC, Mich. (AP) — Michigan investigators and out-of-state police are tracking down more than 30 recalled diesel vehicles that were stolen from the parking lot of a shuttered arena in southeastern Michigan.

Indiana State Police Sgt. Jerry Goodin said the Volkswagen cars were part of a recall due to emissions issues and were being held at the Pontiac Silverdome when they were stolen. Hundreds of repurchased Volkswagen vehicles were stored outside the stadium after the company spent more than $1 million to compensate owners of about 600,000 diesel-powered cars that cheat on emissions tests.

Goodin said 32 cars were given fake Michigan titles and shipped to southern Indiana, where a Kentucky business sold them at an auto auction, putting them back on the road. Authorities used Volkswagen's computer system to see the cars were missing.

"Volkswagen was keeping track of all these vehicles they were purchasing back or buying back," Goodin said. "When these VIN numbers started showing up again in their system, that's when the red flags started flying up."

Michigan and Kentucky authorities notified Indiana police about the investigation. Goodin said Indiana police and the Clark County Sheriff's Office in Indiana have retrieved nearly 20 of the cars.

The Oakland County Sheriff's Office is investigating the theft.

"Everybody here is going to be victims," Goodin said. "The auto auction is a victim, the car lots are victims and the individuals that bought them are victims."