Most murder mysteries on TV tend to have a small number of suspects, and the trick is to find which one did it. I get the feeling that real life murders the police either have absolutely no idea who did it, or know exactly who did it and just need to prove that it was them to the satisfaction of the court of law.
That explains why forensic tests (e.g. fingerprints) are used despite being pretty suspect. They convince the jury that the guilty guy did it, which is all that matters.
Most murder mysteries on TV tend to have a small number of suspects, and the trick is to find which one did it. I get the feeling that real life murders the police either have absolutely no idea who did it, or know exactly who did it and just need to prove that it was them to the satisfaction of the court of law.
That explains why forensic tests (e.g. fingerprints) are used despite being pretty suspect. They convince the jury that the guilty guy did it, which is all that matters.
See https://issues.org/mnookin-fingerprints-evidence/ for more on fingerprints.