This trope describes situations in which a character or investigative team has been seeking the culprit in a murder or series of murders. The character/team finally locates the murderer, only to find that it was a hired hit, or that it was a proxy murder. They know who committed the actual act, but the case (usually to their expressed chagrin) is not over — they still need to determine who the real mastermind is.
As a Plot Device to force the team to do more investigative work to keep the story moving, things are almost never as simple as "ask the killer who hired you". It could be that the killer will escape custody, get killed trying to escape, bite down on a Cyanide Pill, or otherwise arrange things so that his discovery/arrest will not result in the exposure of the true culprit. Particularly common is for them to give in, say, "His Name Is..." and then get his head popped by a sniper... sometimes right off his shoulders. Just as impeding might it be a Mysterious Employer who wouldn't trust his agent with his information. This trope often appears hand-in-hand with His Name Is....
Might be expanded to any form of unsolved mystery, and indeed non-criminal mysteries as well.
A subtrope of Yank the Dog's Chain, as it allows them to tease the audience with resolution ("This week, we find the identity of Leonard's father's murderer!") while at the same time preserving the tension of the unresolved mystery ("...but not why!"). This also makes it a subtrope of Failure Is the Only Option, with the twist being that they succeed in going one rung up the ladder rather than all the way to the top.
Unmarked spoilers follow.
- Ghost in the Shell: Stand Alone Complex had this happen repeatedly during the Laughing Man case.
- Death Note: At Higuchi's arrest.
- The Pre-Crisis Batman, long after he finally tracked down the murderer of his parents, Joe Chill, discovered that Chill was actually an assassin hired by the mobster Lew Moxon who wanted revenge on Thomas Wayne for getting him arrested. Batman reopened the case to hunt his parents' true murderer down, a discovery that was especially galling considering Robin pointed out that by leaving him alive, Bruce was manipulated to be Moxon's alibi since a 10 year old could not be expected to know that a simple stick-up gone murderous was more than it seemed.
- Starlight Over Detrot: The killer of Hardy and Cosmo, that is.
- In Attack of the Clones, an assassin tries twice to kill Senator Amidala. When the Jedi capture the assassin, Jango Fett enacts this trope with great prejudice.
- The Hydra assassin in Captain America: The First Avenger does this as well after his submarine getaway doesn't exactly turn out as planned.
- Inverted in Isaac Asimov's The Naked Sun. Lije catches the murderer, but deliberately lets the killer go free.
- Averted in Tom Clancy's Red Rabbit. Jack Ryan catches an Eastern Bloc assassin moments before an attempt on the Pope's life, but fails to realize that there was a hired gun until he opens fire. In this case the assassin in hauled off, while the gunman is found dead in a car later on.
- This happens four times in Castle. The first time, Castle and Beckett find the man who murdered Beckett's mother and find that he's a hired killer, but Beckett has to shoot him in order to get Castle out of a hostage situation. The second time, Beckett manages to capture another hired killer, a sniper, who was hired by the same person(s) who ordered her mother's murder. This sniper is still alive by the end of the episode, but indicates with a stone-faced glare that he'll never inform on his clients. The third time involves a key person involved (really, really complicated) with her mother's murder- Police Captain Montgomery! She gets to talk to him uninterrupted, and he knows who the mastermind behind the conspiracy is, but refuses to say the name anyway, saying that the mastermind is so rich and powerful that giving her his name would get her killed as certainly as if he'd shot her himself. He dies minutes later. And Beckett is shot during his funeral, making it a Senseless Sacrifice. Or not so senseless, as the sniper broke into Montgomery's house looking for info on Beckett's protector; she's able to confront him, but fails at defeating him. He puts Beckett's protector in the hospital, then tries to find the incriminating files hanging over his boss's head...only to be killed by a booby trap on them. This destroyed the files...but after sifting through them, they figure out who the boss was...but they can't touch him because he's a high-ranking Senator.
- Not entirely senseless. Montgomery took some really bad men down with him, and Beckett has much better chances of surviving that single gunshot than surviving a close encounter with a car full of hitmen.
- This also occurred twice in Monk, with the identity of Monk's wife's killer:
- First, in season 2, Dale the Whale gives Monk the name of the man who built the bomb that killed Trudy. This man (Warrick Tennyson) cannot name the man who hired him, but he mentions that the man had six fingers. Nearly four seasons later, we learn the Six-Fingered Man's name (Frank Nunn), but he too was only a hired hit-man. It's not until the final episode that the real murderer's identity is revealed.
- With the Tie-In Novel Mr. Monk Is Miserable a variant happens, in that there is no hired killer, but a young woman who is stabbed as she is about to talk to Monk and Natalie was killed simply because she knew the identity of a skull Monk found in the Parisian catacombs.
- Continuing the trend of single-word titles, Life season one ends with the capture of the man who really killed Crews's business partner and said partner's wife and family. But the Man Behind the Man gets to him in prison, so Crews still doesn't know why they were killed. It was so he would make a Face Heel Turn and become the new commander of the evil forces.
- This happens routinely in Burn Notice. Every time Michael spends half a season tracking someone down, they suddenly die.
- Inverted in the How to Get Away with Murder episode "It's All My Fault". Sam Keating, who was killed in self-defense by the student protagonists, is definitely The Murderer. The Killer Frank Delfino remains at large as only The Killer, The Murderer and the audience are aware that there was anyone else involved.
- The Due South pilot follows Benton Fraser as he heads to Chicago on the trail of the killers of his father. He tracks down the hired assassin who did the deed, only for a friend of his father's to shoot the hitman in cold blood, ostensibly because he wanted revenge but really because he was the one who ordered the hit.
- This is explored in L'étrange mort de Paul-Louis Courier, an episode of La caméra explore le temps relating the real-life murder of a political writer in 1825. During the first investigation, Louis Frémont, Courier's keeper, is suspected but eventually acquitted due to insufficient proof and the lack of motive for the murder. Four years later, new reveals firmly establish Frémont's culpability... but Judge Hainique is still unable to figure out why he killed Courier, and since Frémont was already judged and acquitted, it is impossible to try him again for the same crime. Even though Hainique becomes firmly convinced that Courier's wife Herminie is behind the murder, he now has his hands tied, since he can't expect a jury to condemn the instigator while the actual murderer remains free. The narration concludes that even today, we know for sure that Frémont killed Courier but we can't explain why.
- In the NCIS episode "Shabbat Shalom", an assassin attacks Director Vance's house, killing Eli David and Jackie Vance. Ziva wounds him with a gunshot during his escape, allowing her and Gibbs to catch up to him—but before they can interrogate him, he poisons himself.
- Trying to find clues as to who really killed Lady Eve on Black Lightning, Jefferson and Anissa discover the body of the sole surviving assassin. Jefferson lampshades the trope by noting the "second rule of high profile assassinations; always kill the killer."
- Phoenix Wright: Ace Attorney - Justice for All has a complete inversion during case 4 in which the this trope is turned around. At first the killing seems like a straight forward murder. It however turns out the one who did the actual killing was a hired assassin. The one who hired the killing however is the one who eventually gets caught, while the one who did the actual deed is never given his just desserts.
- Ace Attorney Investigations: Miles Edgeworth: Edgeworth uncovers Shelly de Killer in case one but is unable to find out who hired him before he escapes. On top of that, it turns out he hadn't killed anyone that day anyways.