> Serious miscarriage of justice cases in Japan involve police deliberately faking the police evidence (and insufficient supervision by the prosecutor to spot such rogue behaviour) such as where the police already knew (or suspected) the location of the body or the murder weapon but they fake the police record to make it appear that it is the suspect who revealed the location.
It's also not difficult for police to do this purposely or even by accident when they don't know the information yet, but there are only a small number of plausible answers to the question. So they ask you two dozen questions that each have five plausible answers, investigate the answers you give and five of them turn out to be correct by random chance. Then the wrong answers are forgotten or written off as a guilty person casting misdirection while the probability of each correct answer is incorrectly multiplied by the others to produce a strikingly inaccurate probability result.
It's also not difficult for police to do this purposely or even by accident when they don't know the information yet, but there are only a small number of plausible answers to the question. So they ask you two dozen questions that each have five plausible answers, investigate the answers you give and five of them turn out to be correct by random chance. Then the wrong answers are forgotten or written off as a guilty person casting misdirection while the probability of each correct answer is incorrectly multiplied by the others to produce a strikingly inaccurate probability result.