Trivia: The movie is loosely based on Sister Prejean's experiences with two real death row inmates, Robert Lee Willie and Elmo Patrick Sonnier. Both men were electrocuted. In the movie, however, Sean Penn's fictional character was killed by lethal injection--because the image of a man strapped down to be injected allows for all that Christ symbolism.
Trivia: When Sister Prejean is back at the convent after Matthew's appeal is denied and his death sentence has been determined to go forward, she is playing games with some kids. A playing card is tossed her way, which she grabs and exclaims "Look! I got an ace!" In fact, the card she's holding is the ace of spades, commonly referred to as "the death card" - a not so subtle pun.