Officers from the Met's Central Football Unit are reviewing CCTV footage after a number of items were thrown towards Manchester United's coach ahead of a match with West Ham United on Tuesday, 10 May.
Damage was caused to the coach but there are no reported injuries to the passengers.
Four male officers suffered minor injuries as a result of the objects thrown. No arrests have been made so far in connection with the criminal damage caused to the coach.
Enquiries are ongoing.
Three men were arrested during the course of the match: A 20-year-old man on arrested on suspicion of affray; a 47-year-old man and an 18-year-old man were arrested for pitch incursion. They have all been taken to an east London police station for questioning.
Anyone with information regarding the criminal damage to the coach and objects thrown should contact police on 101 or Crimestoppers anonymously on 0800-555-111.