The two assistant referees and fourth official on duty in Sunday's controversial Chelsea-Manchester United clash look set to give their full support to referee Mark Clattenburg in the Football Association's forthcoming investigation, Press Association Sport understands. Chelsea lodged a formal complaint with the FA on Wednesday night over the "inappropriate language" they claim Clattenburg used against John Obi Mikel in their 3-2 defeat at Stamford Bridge last weekend. The club have submitted a dossier of evidence which contains accounts given by the players, who allege the 37-year-old official used a term which has been interpreted as racist. Clattenburg denies the allegation and it is understood that assistant referees Michael McDonough and Simon Long and fourth official Michael Jones also believe he is innocent. Press Association Sport understands the trio did not hear anything untoward from the referee during the match on their linked headsets and are expected to say as much in any testimony given to the FA. It is understood that the professional refereeing community as a whole has been deeply upset by the allegation against Clattenburg, who himself is determined to clear his name. Other well-respected current and ex-referees will offer positive character references for Clattenburg's defence if the County Durham official has to answer any charges from the FA or the police, it is understood. If the procedure for previous disciplinary cases is followed, Clattenburg is likely to be the last person that the FA interview as part of its enquiries. It is expected that the body will firstly look at Chelsea's dossier and then speak to McDonough, Long and Jones before interviewing the man who was in charge of the game. Chelsea released a statement on Wednesday night confirming they had submitted a complaint over Clattenburg's alleged comments towards Nigeria midfielder Mikel. The London club dropped a complaint regarding a comment alleged to have been made by Clattenburg to another of their players, thought to be Juan Mata. | 
