> How many people have been wrongfully convicted because the police needed to get the crime off the books, or evidence was misleading, or eyewitnesses gave false testimony?

There are numerous cases where people have been wrongfully convicted even though the police and the prosecutors had evidence indicating that they were innocent. This is especially true for prosecutors, and has been hashed out so many times I won't even bother linking to any specific article - just google for "prosecutor withheld evidence of innocence", and read a couple of stories that pop up in search results. Worse yet, the American legal system refuses to acknowledge this practice as unequivocally wrong and a miscarriage of justice