MINNEAPOLIS (AP) — Federal officials have accused four Minnesota men in a multi-million-dollar scheme to transport stolen catalytic converters to buyers in several states. The indictments were announced Tuesday. All four men are charged with conspiracy to transport stolen property interstate. Two of the men face additional charges. Court documents say the men acquired stolen catalytic converters and transported them to buyers in New Jersey, New York, Oklahoma and Colorado. The conspiracy allegedly resulted in about $21 million in payments to the men. Thefts of the devices have become problematic nationwide in recent years. Once stolen, they are often melted down for their valuable metals.