The mystery man accused by Amir Khan of "interfering" with the scorecards of the judges in the boxer's world title defeat by American Lamont Peterson was an IBF official, the Briton's promoters said Friday.
Khan, who lost his WBA super-lightweight and IBF light-welterweight crowns to Peterson last month, posted a number of messages on Twitter Thursday and highlighted footage from the fight as he questioned the appearance of the unidentified man at ringside.
The Briton's camp had already lodged an appeal against the result of the Washington fight, with a decision expected later this month.
The IBF has declined to comment until after the January 18 appeal hearing but Golden Boy chief executive Richard Schaefer told Sky Sports News the unidentified man was an IBF official who was not assigned to the bout.
"The IBF requested credentials for this man through the Washington DC boxing commission. We were told by the IBF he does work for the IBF but that he was not assigned for that fight. Therefore it's even more troubling," said Schaefer.
"Why was he sitting there and why didn't anyone from the IBF remove him or tell him he had no authority?
"He identified himself to our staff as an official of the IBF and that he had the right to sit there and the fact the IBF supervisors allowed him to sit there is really quite astonishing," added Schaefer.
"What's further astonishing ... is he was permitted to actually touch and be handling the scorecards ... the plot thickens and we're going to continue our investigative work here."
Schaefer said he had been given legal advice not to name the mystery man.
In the footage highlighted by Khan, a man can be seen next to WBA supervisor Michael Welsh.
He then appears to reach across in front of Welsh. The boxer's camp allege that it was at this point the mystery man interfered with the scorecards.
Schaefer said the footage was "shocking" and called for the fight to be declared a no-contest.
"I do believe there's enough controversy to warrant a no-contest decision," he added.
"At the very least I think both sanctioning organizations should order an immediate rematch and then the two fighters can settle the score in the ring."
Gilberto Jesus Mendoza, vice-president of the WBA, agreed.
"There should be a direct rematch," Mendoza was quoted as telling media. "You have to guarantee fairness, you have to guarantee that no one who isn't directly involved can sit at the table.
"I cannot take anything away from Mr Peterson but there were a lot of things that make this fight controversial."
Khan, the 2004 Olympic lightweight silver medallist, said earlier Friday the mystery man celebrated with Peterson after the American won the fight on a split decision.
"You only see that on the video -- at the fight I didn't realise," Khan told Sky Sports News.
"But after watching it on tape you see him around the same corner as Lamont Peterson's team, cheering with them and celebrating," added the 25-year-old.
"That's the reason I want to know who this person was and why he was sat with the judges? Why was he passing papers around? Why was he handling things?
"The rule is whenever the judges are working, no one is allowed to touch the judges' papers or scorecards.
"Were they scorecards? I don't know. That's the thing I want to know and that's the complaint I sent out. The WBA have promised me, within the next 24 hours, they're going to let me know exactly what happened," said Khan.
"All I want is a rematch. I've offered the fight to him and he's not taken the fight, maybe he knows he would get beaten and he was beaten in that last fight and that's why he doesn't want to take the fight."