U.S. authorities are investigating whether supplier giant Robert Bosch GmbH conspired with Volkswagen to create emissions-cheating software and hardware and whether automakers other than VW used Bosch software to defeat emissions tests involving diesel vehicles, Bloomberg reports. The expansion of the investigation comes almost a year to the day since the EPA announced Volkswagen had used so-called "defeat devices" in their 2.0-liter diesel models in hundreds of thousands of cars over a period of several years, an accusation that quickly prompted speculation that at least one outside supplier may have known about the efforts.