Aaron Low is a father who leads a church, and ministers to certain prisoners also. He was a suspect in the murder of Deon Carver because he was in Carver's office when he died, but he claims that he was already dead. Beckett and Castle discover that he in fact is one of several people with essential knowledge of the lost haul from a massive diamond robbery. Father Aaron, according to what Brooke Carver overheard, argued with Deon about how unchristian it was of him to cut his wife out of a share of the treasure.