@HeliaXDemoN Except this is Japan, and if you're suspected of a crime (or being involved in it) they'll even fabricate evidence against you if need be. If memory serves me right the conviction rate there was ridiculous (though probably not as bad as the US).
@criver@NotTriton
According a good video on the subject, it is mainly because cases aren't opened of they're not completely sure you're guilty, with evidences to support it.
But, I cannot guarantee it's true. Just, it's their explanation.