Jose Mourinho is at the centre of a police probe following a complaint of common assault made against the Internazionale coach in the aftermath of their Champions League defeat to Manchester United.
The Portuguese coach is alleged to have punched a supporter outside Old Trafford as he boarded the Inter team coach following their 2-0 defeat in the second leg of a last 16 tie.
Greater Manchester Police have confirmed they are investigating an allegation of common assault and have requested CCTV footage from United.
"Shortly before midnight last night (Wednesday), a man reported that he had been punched in the face outside Old Trafford," read a police statement.
"We are investigating an allegation of common assault."
After his side's defeat, Mourinho was in gracious mood as he tipped United to win an unprecedented quintuple this season.
The former Chelsea boss suggested Sir Alex Ferguson's side could add the Champions League, Premier League and FA Cup crowns to their trophy haul which already contains the Carling Cup and Club World Cup this season.
"Manchester United have worked together for five consecutive years," he said.
"Right now they are at their maximum level. That is why they are European champions.
"That is why they can win everything."