Professional Game Match Officials Ltd is "aware of the allegations" and "taking them very seriously" after a video appeared to show suspended Premier League referee David Coote snorting white powder.
Comments Coote is alleged to have made about former Liverpool manager Jurgen Klopp and the club in previous video footage have led to him being suspended by PGMOL and investigated by the body and the Football Association.
On Wednesday evening, another video appeared on the Sun's website which it said showed Coote snorting white powder during the summer's Euros in Germany, where he was officiating.
A PGMOL spokesperson said: "We are aware of the allegations and are taking them very seriously. David Coote remains suspended pending a full investigation.
"David's welfare continues to be of utmost importance to us and we are committed to providing him with the ongoing necessary support he needs through this period. We are not in a position to comment further at this stage."
The Sun said the video was taken on July 6, a day after the Euro 2024 quarter-final clash between Spain and hosts Germany, for which Coote was a support VAR official.
UEFA said that it had taken action against Coote earlier in the week.
"The UEFA Referees Committee immediately suspended David Coote until further notice on 11 November - in advance of the upcoming round of UEFA matches - when it became aware of his inappropriate behaviour," a UEFA spokesperson said.
The previous video footage, appearing to show Coote making highly derogatory remarks about Klopp, including reference to the German's nationality, and the Anfield outfit, began circulating online on Monday.
He was suspended by PGMOL pending a full investigation, and the FA subsequently said it was also investigating the matter.
The FA has the power to investigate remarks made in a private context and it is understood part of its investigation will centre on whether remarks about Klopp's nationality constitutes an aggravated breach of its misconduct rules.
That footage has not been verified by the PA news agency but is understood to be being treated as genuine by PGMOL.
Additional reporting from PA
