History Main / INeverSaidItWasPoison

* ''{{Literature/Spenser}}'' gets one of several hints the Stapleton family in ''Small Vices'' is lying about their son and his alleged non-involvement in the case Spenser has been hired to investigate when they specifically refer to it as a sex crime, since the fact that the victim was also murdered was far more likely to be of note to people who had supposedly only heard of it in passing. Their referring to it only a sex crime makes sense when, at the end of the book, [[spoiler:it's revealed it wasn't actually a murder--the victim and their son were playing a sex game involving EroticAsphyxiation and she accidentally died during it.]]

*** In the first case, Shelly de Killer [[spoiler:refers to the victim by his full name during a cross-examination, while up until then Edgeworth had only ever referred to him by surname (and, in fact, didn't even ''know'' his first name until that point). It doesn't mean what you think it means, but it does reveal him as more connected to the case than he claims]].

* ''Film/TheWomanInTheWindow'': Played straight so often that it stops being suspenseful and becomes hilarious; the guilt-ridden professor lets slip every possible detail, including knowing the man was murdered (when the body hadn't turned up yet), knowing where the body was placed, that it happened at night, etc. His friends are so dense that they wave off every comment and never suspect him, but you would think he'd just learn to keep his mouth shut, especially when having casual conversations ''with the district attorney''.

* ''Literature/HarryPotterAndTheChamberOfSecrets'': Dobby inadvertently reveals that he has been stopping Harry's letters when he mentions that Harry's friends haven't written to him -- which he should have no way of knowing.

* As noted, police actually do rely on this as part of real life interrogation techniques. However, over-reliance on this technique has led to a significant number of false confessions and erroneous arrests. Police will either feed the suspect information he didn't know before and he'll repeat it back, and they'll use that to browbeat a confession out of him, or the suspect will make inferences that make it seem like he knows more about the crime than he really does (it's ''very'' easy to assume that the victim was shot in a murder case, for example - and if a suspect says many different things, the police can report only the inferences that were correct, making them sound incriminating out of context). This has caused police in some countries to abandon the technique entirely. There's also the issue that police can accidentally reveal their hand while doing so. If, for example, a detective tries to coerce a confession by saying that they found the suspect's fingerprints and the suspect wore gloves while committing the crime, they will know the police are bluffing and don't actually have any solid evidence.

* An exaggerated version with New Zealand baby farmer John Makin. While awaiting trial, he had told his cellmate that the police could not prove he had poisoned any of the infants under his care. He was right. However, this was because the bodies were too decayed for a cause of death to be established, meaning that nobody other than Makin had ever suggested he had poisoned them.