Ladies and gentlemen, we'd like to raise your awareness of a tragic disorder affecting everyone from common street thugs to criminal masterminds everywhere, Chronic Evidence Retention Syndrome. Responsible for the downfall of many otherwise competent bad guys, CERS can be recognized by some of the following symptoms:
- The pointless hoarding of evidence against oneself even when there's absolutely no need to do so;
- Keeping easily destroyed or otherwise easily discarded evidence intact;
- Having said evidence in a location trivially linked to you; and
- In extreme cases, actually going out of the way to make sure it's clear that something is evidence, and linking it to you.
Please note that retaining evidence of a crime where the evidence consists of, say, something valuable you wanted to steal, isn't symptomatic. In a genuine case of CERS, the evidence will have absolutely no value to anyone other than proving the holder guilty. So be on alert for these symptoms, and so long as the criminal mastermind isn't the Shoot the Messenger type, let him know he may be making a critical mistake.
This trope can be justified for fairly mundane reasons. Stuff that would be considered incriminating evidence after a crime, such as bills and receipts for certain tools and implements, would be a mundane object before the crime. Likewise, people who plan to do something illegal don't expect to get caught, so they never consider deleting or destroying evidence as necessary until it's too late. In addition there is the case of Absence of Evidence, where if you don't have paperwork or implements connecting you or associating you in a certain place or time, it can lead investigators to conclude that you destroyed evidence, provided you don't have an iron-clad alibi. And you know what helps maintain an alibi? Paperwork that connects you to a certain time and place. Likewise if you are working with a group of fellow criminals and associates, some form of incriminating record will be kept, if only as a form of insurance or mutual blackmail.
Generally a subtrope of someone simultaneously holding the Villain Ball and the Idiot Ball. Typically, one can expect the person to be a Smug Snake, thus making his eventual downfall all the more satisfying. If an underling does it, expect the Man Behind the Man to make sure he doesn't get a chance to do it twice. Can be justified by showing the villain to be an avid collector of Creepy Souvenirs. Compare this trope to Orgy of Evidence (where the excessive number of clues in a crime scene alerts investigators that they are being misdirected).
- In both comic and movie versions of Watchmen, Veidt for some reason didn't erase the computer files that detailed his plan to frame Dr. Manhattan for causing cancer and leaving Earth, and information on his ultimate plan, even though the Manhattan plan had been successful (so far as he knew) and he'd already kicked off the second, so there was no need to keep the files at all.
- It's possible that he wanted the files to be found so that his friends would confront him and thus leave New York at the time of its destruction. I mean, why else would the "smartest man in the world" keep them in a computer with not only an obvious password but a prompt that basically says "Password incorrect: you need to ADD ANOTHER WORD"?
- The second arc of Ultimate Spider-Man had Peter Parker stealing The Kingpin's own security tapes and releasing them to the media; said tapes showed the Kingpin killing a man with his bare hands. To top it off, Peter in history class hears about the Nixon tapes and participates in a discussion about this trope. Why did Nixon (and by extension the Kingpin) install these recording measures? Because they believed they were untouchable.
- The Far Side has an imprisoned rodent explain to his cell mate why this trope was his downfall.
I could've gotten away clean with it if I'd gotten rid of the evidence... but shoot, I'm a packrat.
- The Departed reveals in the finale that Frank Costello has recorded all his conversations with Colin Sullivan and given instructions on his death to his lawyer to send the evidence to Billy Costigan. The evidence was mutually self-incriminating and Costello created the records for the sake of insurance. Though since Costello was a rat for the FBI, he could also have been using the recordings with the intention of selling out Sullivan down the road.
- In You Only Live Twice, SPECTRE not only kept a photograph of their smuggling ship, but they helpfully annotated the fact that they killed the tourist who took it, thus providing a clue for James Bond as to where to look.
- Minority Report subverts and lampshades this. When John Anderton searches Leo Crow's apartment, he finds the bed is covered in photos implying that Crow kidnapped and molested dozens of children (including Anderton's own son). Then it turns out Crow is innocent, and the photos had been faked and set up solely to give Anderton motivation to kill Crow. Later, Detective Witwer examines the apartment, and immediately (correctly) deduces that Crow had been set up, on the logic that real criminals never leave behind this sort of "orgy of evidence".
- Upstream Color: The Sampler documents all of his victims in some sort of quasi-scientific study, though what he does with this information is not entirely clear. He's never seen studying his documents after the fact and only seems to use his victims to inspire his music.
- In Hot Tub Time Machine, Adam keeps a box marked "Cincinnati" in his closet, which is apparently evidence of a shameful and shocking Noodle Incident. His friends are horrified that he'd not only keep whatever is inside the box, but plainly mark it "Cincinnati." Adam protests that he can't just throw something like that away, and he had to mark it so he'd know which box it's in.
- Lampshaded and averted in The Godfather, Rocco Lampone carries a revolver with taped grip and trigger (to prevent fingerprints) and Clemenza tells him to leave it at the scene to prevent it from being traced back to them.
Clemenza: Leave the gun. [beat] Take the cannoli.
- The Nightingale Killer in Frequency had a box with trophies and newspaper clippings, stashed in a hidden compartment in a closet in his apartment. Once John identifies the killer in 1999, he sends his father (in 1969) to the address to find it, since the police knew that the killer always took mementos.
- Note to the Reigate Squires in the eponymous Sherlock Holmes story: when the international intrigue hero who's been all over the papers is sacked out in your parlor, that's probably your last chance to destroy anything incriminating. Also, if said incriminating paper has a piece torn off, you might want to wonder about that.
- In The Fourth Protocol by Frederick Forsyth, a jewel thief plans to burn a briefcase from his latest job (and his fence scolds him for still having it). But it's such a nice one, he can't bear to, so he checks to see there's no identifying marks and keeps it. However it's someone else who gets burned; after his fence is murdered by men searching for the case, he examines it a second time and discovers a hidden compartment full of top secret documents.
- In The Blacklist, the Stewmaker's entire job is to completely destroy the evidence of other people's crimes, but he still compulsively collects souvenirs from each job that he does.
- A heroic subversion in Burn Notice: after Michael Westen is framed for murdering his CIA liaison, the first thing he does is get rid of the murder weapon. By destroying it with thermite.
- Daredevil (2015): Wilson Fisk largely averts this, being careful to eliminate anything that can be traced back to him. Except for what does him in in season 3, which is when he has Dex's "north star" Julie Barnes killed, as well as the bodies of the two hitmen hired to shoot her, and rather than dispose of them, he has Felix Manning throw them in a meat locker for preservation. Dex thus finds out the truth when Matt tortures this information out of Felix.
- In an episode of Hawaii Five-0, once the bad guys steal the evidence that Steve McGarrett's father had been investigating, they keep it for some reason instead of just burning or shredding it, which allows an employee to steal some of it and leak the info back to McGarrett, leading him to the person who ordered his father's death.
- Luke Cage (2016): Mariah Dillard has a .38 revolver that she has a particular sentimental attachment to. The revolver had been first used in the 1980s by Cottonmouth to kill their uncle Pete, who was raping Mariah. 30 years later, in season 1, she gives the gun to Shades to use to kill Candace Miller. Then in season 2, she uses the gun to execute Bushmaster's uncle Anansi after killing a bunch of people in his restaurant and setting him on fire. Misty Knight makes a connection between the three murders thanks to the ballistics reports, however, linking the gun to Pete's murder is problematic as that case was handled by Misty's late partner Scarfe, who turned out to have been on the Stokes' payroll. When Shades begins cooperating with the police to bring Mariah down, part of the deal is that he lead the police to the revolver as that's the most damning evidence to incriminate Mariah.
- An episode of The Persuaders! involved a crucial piece of evidence that the culprit couldn't work the will to destroy, despite his henchman's urging: A gift by Adolf Hitler himself for helping the defeat and surrender of France.
- The Wire:
- Generally averted with guns. Most criminals are always shown dumping their guns into storm drains or, if they can't do that, wiping them with their shirts and throwing them away. Even the otherwise dumb-as-bricks ones are smart enough to listen to their cleverer colleagues and dump their guns. But it's not always perfect. In "Stray Rounds," Bodie and his crew get involved in a shootout with a rival crew in which a kid in an apartment on the corner was hit by a stray. Stringer tasks Bodie with getting rid of the guns, which Bodie does so by tossing the bag over the side of a bridge. Unbeknownst to him, they land on a barge, and are turned over to the police. Fortunately, the guns were wiped clean beforehand, allowing Bodie to resist Cole's attempt to bluff him in the interrogation room.
- The only time a criminal retains his gun, it's because Bird has a particular attachment to the weapon, a chromed Makarov, and ends up with life without parole for his sentimentality.
- Narrowly averted when Stringer forms his "co-op". In his spare time from being The Dragon for the Barksdales, Stringer is taking business classes at the community college. When he has to step up and lead the street operations due to Avon being locked up, he applies his education, going so far as to hold "staff meetings" for the dealers that are conducted according to Robert's Rules of Order. Then he takes it further, convincing the city's other kingpins to join him in a co-op so they can get a bulk rate on shipments of drugs and reduce the violence. At the first meeting, he notices his assistant Shamrock writing on a legal pad.
Stringer: Muthafucka, what is that?
Shamrock: The Robert book says we gotta have minutes for a meeting, right? These the minutes.
Stringer: Nigga, is you taking notes on a criminal fucking conspiracy? [destroys pad] The fuck is you thinking, man?
- Played with Phoenix Wright: Ace Attorney's bonus case, "Rise from the Ashes." The culprit keeps a critical piece of evidence hidden away which he's used to blackmail someone into doing his bidding; revealing this evidence when prompted will have dire consequences, but concealing it (temporarily) will force the culprit to tip his hand, and the new context in which the evidence is ultimately presented points the guilty finger at him instead.
- Noticeable in Fallout 3 and Fallout: New Vegas. Whenever you get a quest to investigate someone, you usually just need to pick the lock of his vault or hack into his computer to find a note explaining his wrongdoing. It's also not rare to find someone's password written in a fairly conspicuous place. One of the most notable instances is Boone's companion quest in New Vegas: the guilty party actually kept a receipt stating how much they were paid for doing the task. It's so obvious that if it weren't for Word of God that they're the actually guilty party, the player could be forgiven for assuming that it was actually a frame-up.
- In Dishonored, the Lord Regent has an audio log locked in his personal safe that has him talking about how he not only framed Corvo, but personally released the plague to Kill the Poor. You can then broadcast it throughout the city, leading to the guards arresting him.
- You can then kill him if you wish as he is being escorted out.
- Danganronpa: Trigger Happy Havoc: In the third case, one character finds an entire hidden room stacked with revelation-packed documents, left there for no apparent reason. The room holds enough importance that The Mastermind is willing to come out of their hiding place to attack The Hero via Tap on the Head while in the midst of reading a single page, before running off with the entire bookshelf's worth.
- Happens twice in Ultima VII Part II. Two hired killers (working separately for two completely unrelated villains) will have incriminating letters from their employers on their corpses - each even stating specifically to destroy the letter after reading! At least a dozen other letters can be found explaining people's various schemes and plots when sensibility would mandate destroying them.
- Happens to many Scooby-Doo villains, who leave out clues all over the place for meddling kids to find.
- Richard Nixon and the Oval Office recordings. In this case, Nixon was under the belief that as a president he had executive immunity and that obviously these tapes would never be revealed to the people.
- Nazi Germany, after the war, the Allies were astonished at the amount of evidence and paperwork related to The Holocaust they were able to uncover. The sheer amount of incriminating evidence pretty much made the convictions at the Nuremberg Trials a foregone conclusion.
- Well, they DID start to shred stuff, but only when it was way too late for them. A lot of that shredded material is still being sorted out today. Upon the approach of the Red Army, the Nazis started destroying and demolishing various concentration camps and extermination camps. They completely destroyed Treblinka, Sobibor and others, and tried to demolish some of the surviving camps before it was too late. There is only one extermination camp that is nearly completely preserved, and that is Majdanek. The reason for its preservation? It was the first camp to be liberated. This is the mundane reason why estimates for The Holocaust can never be completely and accurately determined, because some of the evidence is destroyed.
- The other reason why the paperwork exists is that the Nazis believed that their actions were legal and sanctioned, and the best way to give those actions that appearance was via paperwork. The paperwork was also necessary since the Holocaust also used inmates and victims as chattel slavery for various corporations and factories both in Nazi Germany and the Generalgouvernment (Nazi-Occupied Poland), and these organizations were run with the usual diligence and order. None of them expected that this evidence would become incriminating after it stopped being necessary.
- Being German, The Stasi of East Germany did the same thing as the Nazis mentioned above. They also tried to shred at least some of it, mostly to no avail. The paperwork used by the Stasi obviously served a practical function in the running of a Police State, since the files, information and evidence accumulated provided a stable database of blackmail. It's just that nobody expected the GDR to collapse and their legacy to be discredited.