The investigation into the Celtic penalty U-turn has been passed to the Scottish Football Association's referee committee.
Assistant referee Steven Craven resigned from the professional game amid a backlash over his part in referee Dougie McDonald's decision to rescind a penalty award for Celtic during their 2-1 victory over Dundee United on October 17.
SFA chief executive Stewart Regan has been looking into the incident in one of his first tasks since taking on the role.
"During this investigation, I spoke to the match referee, Dougie McDonald, his assistant, Steven Craven, Hugh Dallas, the head of referee development, and Jim McBurney, the referee observer.
"On concluding my own investigation, and adopting due process, the matter has now been referred to the referee committee for consideration at their next scheduled meeting, which will be held on Friday, October 29.
"It would therefore not be appropriate to comment any further until the committee has met."
Craven quit after he and his teenage sons were reportedly the subject of threatening remarks and verbal abuse.
Craven was reportedly angry that the SFA did not make clear that he had not instigated the discussions with McDonald, before the referee withdrew his penalty award following United goalkeeper Dusan Pernis's challenge on Gary Hooper.