In my country a judge discides if a crime has been committed.
How does the police decide if they should put handcuffs on someone in the first place? I bet a judge is not involved.
We have the trias politica. Police enforce laws made by the government. They don't descide if an actual crime was committed because everybody is innocent until proven guilty, this is where the judge come in to play to descide if the alledged crime is in fact a crime. This is to prevent an absolute authoroty.