Since Saturday's thrilling Premiership match between Celtic and Rangers, police launched an inquiry into the allegedly threatening communications received by referee Kevin Clancy.
Ange Postecoglou’s team moved 12 points clear at the top of the table following their 3-2 Old Firm victory at Celtic Park.
Rangers boss Michael Beale said Clancy got two major decisions incorrect, with the Ibrox club subsequently writing to the Scottish Football Association seeking an explanation for one of them - an early goal from Alfredo Morelos, which was disallowed.
