Episodes of detective series are rarely happy with just one murder. There has to be two or three, with the second being found just before an ad break. Frequently the second murder only confirms the detectives' suspicions, especially if the original murder was disguised as a suicide or accident. If the prime suspect for the first murder is the next victim, it's Suspect Existence Failure.
This is also sometimes necessary to establish a pattern to the murders. If one librarian is killed, it could be a random crime. If two librarians are killed, then someone is targeting librarians.
- Most of the murder motives in The Kindaichi Case Files is revenge against one's tormentors, and they usually succeed to kill all but one of the people who had wronged them in the past.
- Forms the plot of the movie Very Bad Things. The first death was an accident. The protagonists' attempts to cover it up lead them into a string of murders, eventually reaching the point where they start killing each other, afraid that one of them will talk.
- The movie A Shot in the Dark has several murders, though many of these are botched attempts to kill Inspector Clouseau. The play it was based on had only one murder.
- Marv's story in Sin City starts off with just one murder but it is soon revealed that the Big Bad is a Serial Killer who has had many victims. Similarly, Marv is "killing his way to the truth."
- Clue the Movie starts out with one murder (Mr. Boddy, the victim from the game), but that one turns into six over the course of the film.
- In the Don Knotts/Tim Conway mystery comedy Private Eyes, Lord and Lady Morley are murdered, and when the detectives come to investigate, the household staff themselves begin to drop like flies, supposedly murdered by the ghost of Lord Morley. Subverted when it is revealed that Lord Morley never actually died, and the household staff had been faking their deaths in order to expose Lord Morley's adopted daughter Phyllis, who had murdered Lady Morley and attempted to murder Lord Morley. So, only one person died after all.
- In Crooked House, The murder of Ass Hole Victim Aristide Leonides is followed later by the more baffling (and seemingly motiveless) murder of Nanny; although it does clear the two characters who had been arrested for the first murder.
- Agatha Christie's detectives (particularly Hercule Poirot and Miss Marple) would often posit that once someone has committed a murder for a dire reason, it becomes easier to kill again (often to cover up the first crime), and then increasingly easy after that, until the killer is acting on the most trivial of threats or slights.
- In The ABC Murders, a serial killer hides the murder that would benefit him amongst a series of others, creating an ABC murderer. "When are you least likely to notice a pin?" "When it's in a pincushion!"
- This is also lampshaded in the book, where Poirot and Hastings discuss detective stories, and Hasting says that more than one murder makes them more exciting.
- Also happens in A Murder Is Announced, where Charlotte, who's been posing as her sister Letitia all this time murders her best friend and another one of her friends for coming close to discovering that she was responsible for the first murder of the man.
- Other examples include Cat Among the Pigeons in which there are three murders committed by two people with entirely different motives who are not working togethernote and The Clocks in which a second murder is committed to help cover up the first.
- Raskolnikov in Fyodor Dostoevsky's Crime and Punishment kills the miserly pawnbroker as per his original plan, and then, without coming to his senses, kills her younger sister who just happened to walk into the room. This is used to support the Aesop.
- Crime writer Harriet Vane describes this trope in the Lord Peter Wimsey novel Have His Carcase:
'No; well, there's the Philo Vance method. You shake your head and say: "There's worse yet to come", and then the murderer kills five more people, and that thins the suspects out a bit and you spot who it is.'
'Wasteful, wasteful,' said Wimsey. 'And too slow.'
- There's a particularly unpleasant variant in the G. K. Chesterton Father Brown story "The Sign of the Broken Sword." An army general murders the major who discovers he's been selling secrets to the enemy, then covers it up by leading his unit into a battle he knows they will lose, to create more bodies.
- Rita Mae Brown's long running mystery series, Mrs. Murphy Mysteries involving Harry Harristeen and her pets always follows this. At some point in the first 50 - 100 pages someone will die. Then two or three other people. It is always easy to narrow the list of people going to die because they are appearing in 'cozy' Crozet, Virginia for the first time.
- A common occurrence in the Kinky Friedman novels. Often Kinky is implicated, not always, but often.
- In Donald Moffitt's Short Story "A Snitch in Time" (published in Analog SF And F), the cop hero, Delehanty, is killed by the murderer he's been chasing, which finally results in the murderer being caught.
- In Death series: This trope is used many times throughout the series. Memory In Death and Fantasy In Death are the few expections. Sure, both stories had the murderer try to kill someone else, but the victim survived.
- Shows up a few times in Henning Mankell's Kurt Wallander novels.
- Jo Nesbø's Harry Hole novels are fond of including serial killers (or killers that appear to be serial killers), so naturally this trope shows up several times.
- In Val Mc Dermid's Clean Break Kate Brannigan puts a second case on a back burner, ruling the murder to be an accident, until more people start dying and she severely regrets it.
- The suspicious death of Sam Westing sets off The Westing Game. During the course of the "game", one of the potential heirs is found dead. Subverted, though. Sam was Faking the Dead to disguise himself as the heir who ended up dead... and his second death was also fake.
- Sage Adair's cases always see bodies stacking up, usually people who knew too much.
- Taggart is notable for this, with only two or three cases of this not happening, as is Midsomer Murders.
- This one happens a great deal in Monk, but "Mr. Monk and the Actor" gave it an ironic twist. A character asks if the murderer is likely to strike again; he's told that it was a crime of passion, and the man who did it will probably never put another toe out of line. Cut to the murderer breaking into a pawnshop to cover up evidence of the original murder, which leads to his second murder when the pawnshop owner walks in on him. He continues to escalate from there.
- Watch an episode of The Inspector Lynley Mysteries, Foyle's War, Inspector Morse, or Lewis. Just about any episode. You cannot escape this trope in recent British mystery/crime and punishment series.
- In Days of Our Lives, the Salem Stalker killed one woman (who was going to marry the man she loved) and was forced to keep killing people in order to cover up the murders. Naturally, another villain took the opportunity to bump off her husband, figuring she'd frame the serial killer for that attack. The cops weren't fooled.
- In a skit for BBC's Children in Need, DCI Burke and DI Rebus (both detectives from ITV) meet at a motorway service station halfway between Glasgow and Edinburgh, where a man's been murdered. Rebus' female detective companion expresses her concern that there might be another murder. Burke's response:
"This is The BBC. You don't need another dead body to keep people watching after the adverts."
- Midsomer Murders has been a frequent user of this trope up throughout its long run, though in the last couple of years, we've actually gotten through an episode here and there with "only" one stiff.
- New Tricks likes to play with this. A number of cases where we are led to believe follow this trope, turn out to be just one murder or even just a single accidental death. Other times the murders are related but perpetrated by different people for different reasons.
- Nearly ever episode of Criminal Minds deals with a serial killer. Or a spree killer. Or someone sociopathic enough to cover up his more regular crime with at least one dead body...
- In the Supernatural episode 'Usual Suspects' in which the boys get arrested for the first time, the killer in the case turns out to be this, a crooked cop covering his tracks, and the supernatural being they were hunting turns out to be his first victim trying to warn the rest.
- Happens in several episodes of NUMB3RS.
- Twin Peaks opens with the discovery of Laura Palmer's murder. It's quickly established that she's at least the killer's second victim, and that he tried to kill a third girl that same night, and he kills two more people over the series - the first to throw suspicion off himself, and the second because she looks exactly like Laura.
- A second (and even a third, fourth...)body very frequently shows up in Silent Witness, often providing the piece of evidence that cracks the case.
- Elementary episode "One Way to Get Off" has two people murdered in a similar way to imprisoned Serial Killer Wade Crewes. Sherlock is ready to believe that one of the original suspects Victor Nardan committed the murders, until another pair come up along with a third victim who Nardan could not have shot with his blind eye.
- The British miniseries Glue starts with a murder of a teenage boy...but then the bodies start piling up.
- In the Midnight Caller episode "The Added Starter," a prostitute vanishes. Since there's no evidence, the police don't believe the one witness who says she was murdered, until her madam is murdered too.
- Older Than Steam: This is most of the plot of Macbeth. Macbeth murders Duncan to become king, and finds himself forced to commit more and more murders for self-preservation.
- Christopher Booker's understanding of the Tragedy plot, well displayed in Macbeth, includes three murders: the Good Old Man, the Rival (or Shadow), and the Innocent Young Girl. Each has symbolic significance. The first murder tends to lead to the others (downward spiral into worse crimes) and the fate of the Girl tends to seal the fate of the tragic hero (ultimate destruction). (It's possible to avoid direct murder of her: violation works (as attempted in Richard III, when he tries to marry Princess Elizabeth, as does driving her toward insanity or suicide.)
- Arsenic and Old Lace: A body in a window seat turns into twelve as the hero discovers that his sweet, innocent aunts have been quietly murdering lonely old men for years.
- Ace Attorney:
- The fifth case of the first game gives us the Joe Darke killings. The titular serial killer accidentally ran over a woman with his car, then killed the two people who witnessed the accident, followed by then the kid who saw him burying the bodies, in order to keep the whole thing quiet.
- And in Trials and Tribulations the killing spree spanned six years. First Dahlia arranged the suicide of Terry Fawles, killed her own half-sister, then poisoned Diego Armando (he survived, barely) and electrocuted Doug Swallow to keep them quiet. If you include Terry this gives her the highest body count in the game. And that doesn't even count her failed murder attempt of Phoenix Wright.
- the white chamber: The killer aka the main character killed her first assistant by accident and hid the corpse, then killed the engineer when he found the body, then murdered everyone else one by one out of sheer psychotic paranoia.
- Usually downplayed, as Monokuma imposes a two-kill limit for each killer to prevent anyone from resorting to a Kill 'em All solution. However, the third chapter of each game generally has two victims.
- A pair of Jägers discuss this trope early in Girl Genius. They talk through the possibility of killing the heroine since She Knows Too Much, but quickly realises that that would force them to kill the witness to her murder in turn, and that "this is turning into one of those plans. You know, the kind where we kill everybody that notices that we're killing people?"
- Parodied in the first "Anthology of Interest" episode of Futurama. The "What If" machine shows what would happen if Leela were more impulsive: she murders the professor and then kills nearly all the remaining cast members to cover it up—except for Fry, who she keeps quiet in another way...
- A kid-friendly variation shows up in Spongebob Squarepants. After acquiring Mermaid Man's belt, Spongebob accidentally shrinks Squidward. He tells himself to calm down so no one will find out, when Patrick shows up and is shrunk by a panicky Spongebob, who continues to zap passersby with the shrink ray. By the end of the episode, he's shrunk the entire population of Bikini Bottom.