About at minute 8:35 into the episode you can see a police officer delivering papers to Det. Esposito. The officer is played by Josh Hopkins.
Castle: Listen if you're not scared, just say it?
Castle: Come on, you know you want to.
Beckett: I don't want to say it Castle.
Castle: For me please.
Beckett: I ain't afraid of no ghosts!
Castle: (to Alexis) I can promise you this. If two people believe in something, really believe, anything, even the impossible, is possible.
Beckett: Why are you so determined to find the supernatural in all this?
Castle: Why are you so determined not to?
Beckett: You know what? I am just following the evidence wherever it may lead, and as a cop, I'm going to consider every possible worldly explanation.
Castle: And what if there is none?
Beckett: Well, then I'm open to the alternatives.
Castle: (laughs) You? Skepticus Maximus?
Beckett: So what's our next step? Are we gonna stake out the house, wait for the demon to show up, zap him with our proton pack?
Castle: That's not a real thing, you know, that real ghost hunters use.
Esposito: Real ghost hunters? Isn't that a contradiction in terms, bro?
Castle: So... if Barry's not our guy, I think it's time we revisit the possibility that our killer's a...
Beckett: If you say ghost, I'm sending you home.
Beckett: (about the blood spatter) Some of it should've landed on the killer.
Castle: Yet every drop of it landed on the floor. This spray is completely unobstructed.
Lanie: Exactly. It doesn't make sense.
Castle: Unless the blood passed right through the killer.
Lanie: Are you saying a ghost did this?
Beckett: Please don't encourage him.
International Episode Titles:
Czech Republic: Démoni (Demons)
"Ghostbusters" by Ray Parker Jr.
Although credited, Penny Johnson Jerald (Captain Gates) did not appear in this episode.
Original International Air Dates:
Canada: October 24, 2011 on CTV
Australia: February 28, 2012 on Channel 7
United Kingdom: April 11, 2012 on Alibi
Germany: April 13, 2012 on Kabel 1
Czech Republic: October 10, 2012 on Prima family
Slovakia: April 10, 2013 on JOJ
Beckett: Maybe Shaggy will keep Scooby out of trouble.
Kate is referring to the famous mystery-solving Scooby-Doo cartoon series that still airs today. The show first aired on CBS in 1969. Scooby-Doo is a talking Great Dane and Shaggy is Norville "Shaggy" Rogers, his owner.
Beckett: (to Castle) I ain't afraid of no ghosts.
An allusion to the lyrics of the theme song for Ghostbusters.