The Metropolitan Police have launched an investigation into an incident at Stamford Bridge which saw a steward injured during Sunday's game against Chelsea.
Manchester United striker Javier Hernandez looked to be the target of objects thrown from the crowd after scoring a 75th minute winner in front of the Matthew Harding stand.
By the time of Hernandez's goal the atmosphere was already on edge within the stadium after referee Mark Clattenburg had sent off Chelsea duo Branislav Ivanovic and Fernando Torres.
A statement released by the police read: "We are aware of an incident during yesterday's match at Stamford Bridge in which a steward was injured. An investigation has been launched into the incident and our inquiries continue."
It is unclear whether the steward was hurt as a result of a missile, with Chelsea quickly releasing a statement which played down the incident and claimed that he "slipped and fell".
The club opened an investigation on Sunday, with a spokesman saying: "We are investigating all the incidents around that time.
"We are looking at reports of objects that may have been thrown or incidents around the steward taking a fall.
"My information so far is that he slipped and fell, may have hurt his knee, and was being treated by the side of the pitch."