Probable Cause
Season 5, Episode 5
Air date October 29, 2012
Written by Andrew W. Marlowe
Directed by John Terlesky
Episode guide
"Murder, He Wrote"
"The Final Frontier"
Castle Season 5 cast
Season 5
Season 5 is now available on DVD.  

1   •   2   •   3   •   4   •   5   •   6

7   •   8   •   9   •   10   •   11   •   12

13   •   14   •   15   •   16   •   17   •   18

19   •   20   •   21   •   22   •   23   •   24

Season 4   Season 6

Probable Cause is the fifth episode of the fifth season of Castle.


While investigating a shocking ritualistic murder, Beckett and her team uncover surprising evidence linking Castle to the killing. As the evidence against him mounts, loyalties are tested, and when surprising revelations come to light, Beckett begins to wonder how well she really knows her new lover and partner of four years.


A woman returns from a trip to discover that her roommate, Tessa Horton has been murdered in an unusually vicious, sadistic and ritualistic way. Her body has been suspended from the ceiling using hooks and razor wire, and an unusual symbol has been carved into her head with a razor.

At his home, Castle confronts someone he believes to be an intruder with his fencing sword, only to discover that it is Alexis, home to deposit laundry and raid the refrigerator for supplies before leaving to attend a class group meeting. As he and Beckett enter the crime scene, Castle gripes that he hardly sees Alexis any more.

The detectives are disturbed by the unusual crime scene they have encountered. Although some prints have been discovered in the hall and on the door, the inside of the apartment has been meticulously cleaned. The victim was also strangled before being displayed on the ceiling, and she was chloroformed to subdue her struggles, and the killer wore surgical gloves to prevent his fingerprints or DNA from transferring to her corpse. This suggests that the killer is calm and meticulous, and that he knows what he is doing and understands homicide investigation procedure, and, as Castle notes that he enjoyed it.

As Castle and Beckett interview the victim's roommate, they learn that she was a shy, workaholic wallflower—but had recently begun dating a man she described as "every woman's fairytale -- rich, handsome and generous." The roommate reveals that she was secretive about the relationship, and that she suspected that the man was married. Ryan's investigation of the victim's phone records reveals that her lover was using a burner phone with a stolen sim-card, thus making him hard to track. Tessa's computer was also wiped, with several emails selectively deleted, suggesting that the killer was covering his tracks.

While the case would seem to have stalled, Esposito pulls Beckett aside after receiving the fingerprint analysis back from CSU. Investigation of the prints found on the door have revealed that there is a pair that do not match either Tessa or her roommate, but do match a set of prints found in the system—specifically, those of Richard Castle. Beckett, surprised, insists that Castle must have actually touched the door as he entered the crime scene, but Esposito replies that CSU are adamants that these prints were discovered before either Beckett or Castle arrived.

When Esposito and Beckett take him aside to discuss the matter, Castle insists that the door was open when he arrived and that he didn't touch it, but affirms Beckett's suggestion that he must have accidentally touched the door on arriving without realizing it. When Esposito presses the matter, Beckett defensively insists that CSU must simply have made a mistake in their timing, and both chide Castle to be more careful at crime scenes when he makes a quip about having a 'evil twin'.

Back at the crime scene, Ryan learns that a neighbor has informed the police that he saw a man stop by Tessa's apartment on the night of the murder, and has given them a description matching that of Lloyd Kurtzman, the victim's boss. Although selected pieces of jewellery have been taken from the victim's possession, once again suggesting the killer covering his tracks, a uniformed officer finds a luxurious earring hidden in the sofa.

On being called into question by Beckett and Castle, Kurtzman lies about seeing the victim on the night of her death. When they challenge him about this, he becomes flustered and uncomfortable, eventually demanding his lawyer. Although Kurtzman refuses to speak, as he is married and has a string of earlier harassment lawsuits against him, as well as a sealed juvenile record, Castle begins to suspect him of the crime. Beckett is troubled, however, by Kurtzman's reaction to their questioning—while everything so far suggests a cool, levelheaded killer, Kurtzman's reaction to questioning suggests the exact opposite, and his lack of an alibi is glaring for someone who had otherwise planned his crime so carefully. 

Castle is willing to put this down to overconfidence, but no evidence tying Kurtzman to the crime is found at his home or apartment, and his juvenile record merely indicates a handful of minor and petty criminal offences—a nothing that would suggest him capable of a murder as vicious as that of Tessa's. Investigating the earring, Ryan learns that it is a rare, unique piece purchased from an exclusive showroom, and while the buyer's name and address are faked and the piece was paid for with a cashier's check, the showroom does have digital surveillance of the day and time that the earrings were bought. As they watch the footage, the detectives realize that the man on the tape is not Kurtzman—and are astonished when the man turns to reveal that he is apparently Castle.

Beckett is again adamant that there must be a mistake and reacts defensively to Esposito pointing out that the evidence is building against Castle. Ryan insists that neither he nor Esposito truly suspect Castle—however, they must follow where the evidence is taking them. Beckett grudgingly concedes the point and authorizes them to investigate Castle's financial records, insisting that Castle can never know he was a suspect. After Beckett storms out, Ryan takes Esposito aside and reveals that Castle and Beckett are in a relationship together. Esposito is naturally incredulously, and Ryan admits that he learnt while the two were in the Hamptons together, but had intended to keep it secret to prevent Gates from finding out and kicking Castle out of the precinct. He says that he is only revealing it now due to the direction the case was taking. The two are adamant that Castle cannot be the killer and are determined to find evidence to exonerate him—a something that becomes a lot more difficult when they discover that Castle apparently withdrew the cashier's check used to buy the earrings.

That night, Castle opens his door to discover his detective friends and a group of uniformed police officers baring a search warrant for his apartment. Initially believing it to be a prank to teach him a lesson after he 'accidentally' contaminated the crime scene, he is increasingly confused and alarmed when the grim-faced detectives soberly inform him that this is no joke—he is a suspect in Tessa Horton's murder. Beckett takes Castle aside and reveals the evidence building against him, demanding an explanation; Castle is unable to furnish one, and the discussion ends in confusion as the detectives discover something very incriminating in his office. As Beckett watches in pain, Espositio reads Castle his rights and arrests him for the murder of Tessa Horton.

The detectives show Captain Gates what they found in Castle's office—a bag, one of a matching set he owns, containing similar hooks and razor wire used to display Tessa and a shirt covered in blood that matches the victim's. Beckett is once again adamant that Castle cannot be the killer ("The evidence isn't the whole story; Castle's taught me that.") and Gates admits that while she is not personally fond of Castle, she nevertheless finds it difficult to believe him capable of the heinous murder the evidence is suggesting.

Nevertheless, they have a job to do, and Gates orders the detectives to investigate his computer and phone records and talk to his family. Knowing that she will feature prominently in his phone records, Beckett begins to reveal her relationship with Castle to Ryan and Esposito, but is stunned when they already know. They confirm that they know what is at stake and will not reveal the relationship to Gates unless it becomes unavoidable. They also question her as to Castle's alibi, and Beckett admits that she was supposed to see Castle that weekend, but he cancelled due to his writing commitments.

Owing to the potential conflict of interest, Captain Gates interviews Castle personally. He insists that he is innocent and that he had no relationship with or knowledge of the victim. He suggests that Kurtzman is trying to frame him, but Gates reveals that Kurtzman has decided to cooperate and has alibied out, having been with a prostitute at the time of the murder and not wanting his wife to find out. Kurtzman has also revealed that he went to Tessa's apartment after receiving a text message that purported to come from her, but instead came from a burner phone; someone tried to frame him. Shaken by the evidence pointing towards him and realizing he has no alibi, Castle demands to speak to a lawyer. Beckett interviews Martha and Alexis, and while they insist he cannot be responsible for this they can think of no one who might have tried to frame him and no way they could have entered their apartment to do so.

As Castle is locked in the holding cell, Beckett insists that she will discover what is really going on and get him released. As he is talking to his mother and daughter, however, Beckett is taken aside by Ryan and Epsosito, who reveal that a search of Castle's computer has uncovered a plan for the murder disguised as a plot-treatment outlining 'the perfect crime'. They also reveal that although the hard drive has been wiped like Tessa's, they have also discovered emails that reveal that Castle and Tessa were having an affair.

Shaken by what she has learned, Beckett tearfully seeks comfort from Lanie. The evidence suggests that Castle started the affair not long after she and Castle got together, but tried to break it off. The evidence overwhelmingly suggests that Castle is guilty, but after revealing how painful it was to watch him be arrested ("He looked like a little boy, he was so scared..."), Beckett once again affirms that she does not believe Castle responsible for any of this: "I know him, Lanie. He is an immature, egotistical, self-centred jackass sometimes. But he's not this."

Brooding in his cell, Castle receives a visitor. Although the man is wearing an NYPD uniform and a name-plate identifying him as "J. Rook", Castle instantly recognizes the man standing before him—it is Jerry Tyson, a.k.a the 3XK Killer. As Castle tries to summon help, 3XK calmly informs him that no one is around to hear, and that the surveillance will not show he was ever here -- "I'm more thorough than that." As Castle confronts him with killing Tessa, 3XK retorts that Tessa is not his 'type', and that people will find it far easier to believe that Castle, a man who plots and writes murders for a living, finally crossed the line and committed a real one. 3XK reveals that he is doing this out of revenge for Castle exposing his earlier plot to fall off the grid and begin killing with impunity, and has stalked Castle for some time planning to destroy his reputation and life before killing him: "People think it's killing that I like, but murder's just an act. It's all about the anticipation, the planning. Watching you and your daughter talking a walk, you and Beckett making love, standing inside your living room, being inside your life, knowing I'm going to take it all away from you. That's what I like."

When Castle insists that Beckett will uncover the truth, 3XK dismisses it—Castle's story will only sound like the desperate pleas of a guilty man, as he has intricately framed Castle and no one will believe his innocence. Furthermore, he has arranged for Castle to be murdered immediately upon arriving at Central Booking the next day after the District Attorney files charges. Beckett's 'punishment' will be to have to live the rest of her life knowing she was unable to save the man she loves.

The next morning, Castle reveals what has happened to Beckett, who confirms that Castle's story does indeed sound desperate and impossible—however, it's also the only thing about this whole affair that make sense to her. Castle is elated to learn that Beckett believes him -- "I never stopped."—and the two briefly hold hands between the bars of Castle's cell.

Beckett takes Castle's story to Ryan, Esposito and Gates. While Gates is skeptical, Ryan and Epsosito confirm that the plot fits with 3XK's previously M.O of intricate plots involving a misdirection, tampering with evidence and even the use of doubles to throw suspicion onto innocent parties. While Gates is sufficiently convinced, as there is no evidence to suggest 3XK's involvement the District Attorney handling the case refuses to grant what she sees as 'preferential treatment' to a murder suspect and refuses to delay Castle's arraignment. Given the nature of the 'tombs' and how prisoners are stacked into cells, any prisoner who has accepted a contract on Castle would find it easy to murder him whether he was placed into protective custody or not, and the possibility of it being a prison guard cannot be discounted. The detectives are therefore, forced to prove that Castle is innocent before he is to be transferred or else his death is all but certain.

As the detectives begin to chase up any shred of evidence suggesting Tyson's involvement, an increasingly desperate Beckett suggests to Esposito the possibility of breaking Castle out. Incredulously, Esposito tries to discourage Beckett, pointing out how easily it could go wrong ("I know how you feel; I love the guy too. But there's nothing we can do.") -- and at that point, Castle's transfer arrives.

As Beckett cuffs Castle to be transferred to holding, they share a moment of intimacy in which Castle jokes that Beckett using the cuffs on him "is so much less fun than the other night at your place." He muses on the first time Beckett ever handcuffed him, at the New York Public Library after he stole evidence during their first case together; "What I wouldn't give to be there now." As Beckett tries to insist that this isn't over and that she'll find a way to free him, Castle assures her that it will be okay whatever happens.

As the precinct watches soberly, Beckett escorts Castle to the officers waiting to take him to Central Booking. As the elevator doors close on him, Beckett vows to find the person responsible for who did this—but moments later, two officers approach Beckett informing her that they are here to collect Richard Castle. To their horror, the detectives realize that the officers who took Castle were imposters. 

As it becomes clear that Castle never made it to Central Booking and the District Attorney prepares to declare Castle a fugitive from justice, the detectives work desperately to find Castle, convinced that 3XK has intervened to kidnap him and kill him personally. While Esposito rails furiously at this, Beckett struck by a moment of realization; remembering his earlier words to her, she leaves the precinct and goes to the New York Public Library—where, in the same room she first arrested him in, Castle is waiting for her, having used his considerable resources to mastermind his own escape and give her a coded message to meet her there. The two hug, overjoyed to be reunited, and while Castle keeps the details of his escape back from Beckett for her deniability, he understands that his reprieve is only a temporary one—not only will every cop in the city be instructed to hunt him down, but once the story breaks on the news his face will be plastered all over the city.

Castle reveals to Beckett that he has been looking into the part of the case that has troubled him the most—how 3XK staged his purchase of the earrings. He reveals that he has discovered an advertisement in an acting trade magazine from several months before calling for lookalikes of famous authors for a private function—himself among them. The publisher of the magazine confirms to Castle and Beckett that the advert was placed for a client who never responded to the headshots that they sent, including one of a lookalike of Castle himself. The lookalike, a waiter who decided to submit for work after people kept asking him to sign Castle's books ("You know, now that I'm up close, I really don't see it.") confirms that he was the one to purchase the earrings, as part of what he believed to be an audition for a reality show; he identifies 3XK as the show's 'producer'. As with the other leads that 3XK has set up, it proves to be a dead end of abandoned P.O boxes and corporate accounts under the name of Joseph Vacher, a nineteenth century French serial killer—however, it does produce a check written to the insurance company Tessa Horton worked for, which in turn leads to a note in the victim's calendar identifying a meeting with a person with the same initials at the address of an empty building 3XK was using as part of his cover.

The team investigate the building, and discover 3XK's lair—along with detailed blueprints of Castle's apartment, surveillance photos, evidence to demonstrate his framing of Castle and a map of the precinct enabling him to enter and exit undetected. Gates assures Castle that in light of the evidence discovered, they will be dropping charges against him for Tessa Horton's murder, although he will still have to surrender himself for his escape from custody and face what will, under the circumstances, likely be a lenient punishment of time served. As a city-wide manhunt for 3XK begins, Gates orders Beckett to escort Castle back to the precinct.

Stopped at a drawbridge on the way, Castle admits that he is unsettled by the easy way in which they seemed to find the evidence exonerating him. He and Beckett share an intimate moment where Castle thanks her for her faith and loyalty, acknowledging that it cannot have been easy to keep believing in him in light of not only the evidence she was faced with but his own reputation and history. She fondly replies that things have never been easy between them, but their moment is brutally interrupted when a van slams into them from behind, pushing them through the bridge's guardrail and nearly over the edge. The driver of the van is revealed to be 3XK, who shoots at the car; after a brief gunbattle, Beckett coldly fires shot after shot into his chest, only for him to get the drop on her as she checks his body, forcing her to drop her weapon in the process. Holding Beckett at gunpoint, 3XK gloats that he wants Castle to witness him murder her. Having found Beckett's gun, however, Castle sneaks up on 3XK from behind and opens fire, causing him to drop Beckett and slip over the edge of the bridge, plummeting into the river below.

The next morning, Castle and Beckett watch as NYPD divers search the river for signs of 3XK's body. Castle is convinced that they won't find anything; having brooded over the events of the case, he has become convinced that he was never truly the subject of 3XK's plot, and Tessa Horton's murder and his own framing were merely an misdirection for 3XK's true goal—to disappear. He is convinced that 3XK has manipulated Castle and Beckett into a position where they would unwittingly help him to fake his own death and act as witnesses to it—now that 3XK is believed to be dead, no one will be hunting for him, meaning he can begin killing again with impunity. Beckett is skeptical and, walking away, tells Castle that he shot 3XK and that everything's over...

... "For now," Castle replies darkly to himself. 


Castle 5x05 Promo "Probable Cause" (HD)00:30

Castle 5x05 Promo "Probable Cause" (HD)


Main Cast

Guest Cast


Esposito: Beckett and Castle? Wha- when did they start? (still slightly in shock after learn about Beckett and Castle)
Ryan: I’m not sure. But I know they were together that weekend in the Hamptons.
Esposito: Why wouldn't she tell us?
Ryan: I guess she was afraid Gates would find out and use NYPD regs to give Castle the boot. I was going to keep it a secret myself, but under the circumstances...
Esposito: Normally I'd be happy for them.
Castle: You believe me?
Beckett: I never stopped.

Featured Music


  • This is the second time that Castle has been detained for a murder. The first time was the season 3 premiere, "A Deadly Affair". As in this case, Castle is just returning from a romantic getaway to the Hamptons.
  • When "3XK" comes to see Castle in holding, he is disguised as a police officer. The name plate on his badge reads "J. Rook." makes reference to Castle's character Jameson Rook in the Nikki Heat series. This also alludes to the fact that "3XK" wrote a dry run of the victims murder. putting it on Castle's computer as further evidence of his guilt.
  • There are references to various prior episodes.
    • In "Flowers For Your Grave", Beckett had Castle arrested for stealing case files, so he could continue to work the case.
    • Castle and Beckett faced similarly Byzantine plots from Jerry Tyson in "3XK" and "Kick the Ballistics". In the former case, Tyson uses faked evidence to frame a (willing) accomplice for his murders. In the latter case, he tricks an abusive cellmate into accepting a stolen gun—Ryan's gun, known to have been stolen by the Triple Killer—knowing the extra scrutiny would ruin his antagonist if he used it.
    • In "3XK", Tyson also stole Ryan's badge, saying it could come in handy one day. However, the fake badge that Tyson wore in his midnight visit to Castle had a different name on it—J. Rook, Castle's thinly veiled stand-in for himself in the Nikki Heat novels.
    • Ryan references "Murder, He Wrote" in explaining to Esposito when he found out about Castle and Beckett's relationship.
  • In "Anatomy of a Murder", Beckett promised that if Castle were ever jailed, she'd break him out. While she considered doing just that in this episode, Esposito dissuaded her. Instead, Castle pulled his own successful prison break.
  • Castle has previously established that he's a crack shot. He out-shot Beckett at a firing range in "Home's Where the Heart Stops". In "A Deadly Affair" (the other case where he was arrested for a murder), he shot and wounded one of the killers to protect Beckett. In "Tick, Tick, Tick..." and "Boom!", a serial killer Scott Dunn frames another man for his killings and targets Beckett; the episode ends with Castle shooting the killer's gun out of his hand, again to protect Beckett. Until "Hollander’s Woods" when he kills serial killer Van Holtzman in self-defense, Castle never actually kills anyone.
  • As referenced in "Flowers For Your Grave", Castle's been arrested many times in the past, but charges have almost always been dropped, usually at the Mayor's behest. This time, Gates intends to pursue charges against Castle for his prison break, though she is confident his sentence will be limited to time served. It's possible that Castle's connections could make this conviction go away as well, though such a high-profile escape will be hard to let slide. Gates made no mention of disciplining her three detectives who harbored him. She may simply have had no choice but to charge Castle even though she knew he wouldn't get any real punishment for his crime.
  • While Judge Markway was mentioned, he did not appear. However, the uniformed police offer played by L.T. Tolliver (and variously called Scott or L.T.) did have a non-speaking role.
  • Except for Gates, everyone in the main cast now knows about Castle and Beckett's relationship. Ryan told Esposito (letting him imply later to Beckett that he'd known all along) and Beckett told Lanie.
  • The actor Paul Anthony Scott who played Castle look-like Paul Dyson is actor Nathan Fillion's stunt double on Castle.
  • This episode aired during Hurricane Sandy, which hit hard on the east coast of the United States.
  • Continuity glitch: Beckett is reading from the crime scene report as she walks towards her desk, Castle takes hold of her hand and guides her to hold a coffee cup by the handle. As she continues walking the shot changes and she's gripping the cup from underneath.
  • Castle's theory about 3XK still being alive is proven in "Resurrection" and "Reckoning" where he resurfaces with Doctor Kelly Nieman to kidnap Beckett. He is finally brought down at the end of the two-parter by Castle and Esposito when Castle draws him into the open with Esposito following him with a sniper rifle then signals Esposito to shoot 3XK who is killed.


Start a Discussion Discussions about Probable Cause

Ad blocker interference detected!

Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.