The average viewer only knows so much about the science and methodology of solving crimes. If they're going to understand your Crime and Punishment story at all, you're going to have to rely on a couple of standard crime-solving tricks. This is the Applied Phlebotinum of the Mystery of the Week.
Though shows have gotten better over the years (probably because the audience has gotten smarter or better informed), quite a few of these tricks don't actually work or don't work nearly as well as they do on TV.
Tropes:
- Bitter Almonds: The evidence smells like bitter almonds, proving poisoning by cyanide.
- Condensation Clue: Steaming a crystal surface to reveal a hidden message previously written on it.
- Conviction by Contradiction: Finding a hole in someone's alibi proves their guilt, with no chance for reasonable doubt.
- Corpse Temperature Tampering: Obfuscating the time of death by interfering with the cooling of a dead body.
- Enhance Button: Impossible image enhancement, often used to identify minuscule cues.
- Facial Recognition Software: Computers can easily scan and identify a suspect based on a photo or video.
- Fingerprinting Air: It's unrealistically easy for the police to find the fingerprints needed for their investigation.
- Forensic Accounting: Cracking secrets by tracing their finances and paperwork.
- Going by the Matchbook: The logo of a book of matches provides a clue to where its owner has recently been.
- GPS Evidence: Your evidence only occurs in a single part of the world!
- Identification by Dental Records: The corpse is so devastated that its identity can only be confirmed by looking at its teeth.
- The Killer Was Left-Handed: Deduction based on the dominant hand of a suspect.
- Locard's Theory: When two things touch there is always a small amount of each left behind.
- Omniscient Database: Highly improbable crime-solving search engines.
- Super Identikit: Police suspect sketch artists are super-humanly good.
- Writing Indentation Clue: Revealing indentations made by the missing, prior page's writing by scribbling on a blank page.
