INDIANAPOLIS (AP) — An Indiana trucking company with nearly 4,000 employees says it filed for bankruptcy and will shut down all operations, just days after two former officials were charged in a fraud scheme.

Celadon Group says it faced significant costs related to a federal investigation and also must deal with debt and “enormous challenges” in the industry.

Celadon said it was the largest provider of international truckload services in North America.

Earlier this year, Celadon agreed to pay $42 million to settle securities fraud allegations stemming from falsely reporting profits and assets.