FRESNO, Calif. (KMPH) -

A federal investigation is underway at the North Fork Rancheria of Mono Indians.

An FBI spokesperson tells KMPH News that agents are searching Rancheria offices as part of an ongoing investigation.

The Department of the Interior is also involved. It protects natural resources and heritage of tribal communities.

The Rancheria has nearly 1,900 tribal citizens -- one of the largest recognized tribes in the state.

For six years, the tribe has been moving forward with plans to allow gaming on 305 acres in Madera County.

Charlie Banks-Altekruse, a tribal representative, issued the following statement:

"We're still trying to figure out what's going on and what we need to do to rectify the situation. It's still evolving. Obviously, they are searching for some information. But we're not sure what it is."

Stay with KMPH News and KMPH.com as we continue to follow this story.