Beckett often steps in to stop him becoming carried away with wild theories that threaten to obscure the facts. He once speculated that a surgeon had been killed for his involvement in an organ-smuggling ring before they discovered that he was wanted for plastic surgery he had performed for someone in witness protection. Castle's writing career has given him a knack for noting minor details in the situations they investigate, such as when he noted that rent for a victim's apartment had been paid for "after" her death.