Tennessee has joined a multi-state investigation into Volkswagen's emissions scandal.
It is one of 28 states participating in a probe into VW's use of secret software to thwart diesel smog tests on nearly a half million vehicles in the U.S.
Michigan Attorney General Bill Schuette's office said Thursday he and other attorneys general will send subpoenas to the German automaker. Spokeswoman Andrea Bitely says many states will investigate both through their consumer protection and environmental protection divisions.
Participating states include Tennessee, Alabama, Arizona, California, Connecticut, Delaware, Florida, Illinois, Indiana, Iowa, Kentucky, Maine, Maryland, Michigan, Mississippi, Nebraska, Nevada, New Mexico, New York, North Carolina, Oklahoma, Oregon, Pennsylvania, Rhode Island, Texas, Vermont and Virginia. Washington, D.C., also is involved.
The Environmental Protection Agency has accused VW of installing a so-called "defeat device" to foil emissions inspections in 482,000 cars sold in the U.S. VW later acknowledged that similar software exists in 11 million diesel cars worldwide.