The fictional town of Bovis, MS was actually filmed in Independence, LA.
Just as the Posse Comitatus Act prevents the military from acting as a Federal Police force on American soil, the CIA's charter does not allow it to act within the United States except in a few narrow circumstances.
Lye is used as a forensic countermeasure to speed up decomposition.
The Hebrew term Abaddon (bottomless pit, or the realm of the dead), and its Greek equivalent Apollyon appear in the Bible as both a place of destruction and an angel of the abyss.
Cointrin, is the former name of Geneva Airport (Switzerland).