Because of a pattern of 25 arsons in Maryland and Washington, DC, a task force includes ATF agents. One question is whether the fire that killed a well-loved grandmother is part of the series. After identifying the homemade incendiary device (a fruit jug, gasoline, a cloth wick, all in a plastic bag), investigators are stymied. A suspect is seen but a sketch produces no results. In spite of DNA evidence from three different fires, the arsons continue without arrest. By the time the arsonist is caught, 44 fires have been set; he is convicted of two deaths as well. No motive emerges until Thomas Sweatt does an interview from prison, confessing a sexual satisfaction, as well as admitting guilt in another case where two people were killed.