After his conviction Anfield man Graham Sankey admitted the attack but his confession was dismissed by Bulgarian authorities.
Now another witness has come foward to insist it was Sankey.
The witness, who asked to be named only as Ian, says the waiter was knocked out by a single punch to the chin by another man before Sankey ran up and dropped the slab on him.
His signed statement has been sent to the court authorities and police in Bulgaria, and Shields's defence team hope to use it at a make-or-break appeal in the next few months.
