I think this was in a PKD short story, but can't remember the title.
Someone gets killed and there is a robot on scene, gathering up evidence. Each successive physical clue - hair, footprint... - narrows it down from the billions of people on the planet, so that, at the end the murderer is found. 10 clues if I remember correctly.
Except that the culprit might have been wrongly identified too, either by a mistake or deliberate deception.