AntonioK

This should have been called as an illegal block. FIVB Rules 14.6.2: "A back-row player or a Libero completes a block or participates in a completed block is a blocking fault." The former of that essentially says they (the back row blocker) can't touch the ball (because the minute contact is made, it's considered "completed", which is forbidden of a back row player), and the latter says they can't participate in a completed block, which is anyone else "legally" touching the ball above the height of the net. Long story short, illegal play, regardless of the ball being contacted by the 4th person or not.