Umm, YES there is a need for an investigation. And for a decision by the D.A.'s office whether or not to file charges, And then a trial to determine whether or not he is guilty. Your Salem witch trial zeal to HANG HIM NOW is what many of us find so troubling, despite the fact that we don't like what Rudin did.
You'd want a fair investigation and trial if you were accused of a crime. "We know enough" is NEVER enough.