Police investigating alleged headbutt on pundit Roy Keane during Arsenal vs Man Utd match

Roy Keane was allegedly headbutted by a member of the public during a football match.
The incident occurred while Keane was working as a pundit for Sky Sports during an Arsenal vs Manchester United game.
Keane was struck in the chin and chest but did not retaliate to the headbutt.
Fellow pundit Micah Richards asked the man to apologize for the alleged assault.
Police are investigating the incident but no arrests have been made yet.