Into the Wild

From the text:

Westerberg had been drawn into a scheme to build and sell “black boxes,” which illegally unscramble satellite-television transmissions, allowing people to watch encrypted cable programming without paying for it. The FBI caught wind of this, set up a sting, and arrested Westerberg. Contrite, he copped a plea to a single felony count and on October 10, 1990, some two weeks after McCandless arrived in Carthage, began serving a four-month sentence in Sioux Falls.