Violence marred the English League Cup tie between West Ham and Chelsea . A 44-year - old man was stabbed in the back and police made 13 arrests . Metropolitan Police are now investigating evidence of violence and offenders . ` The club will not tolerate the unacceptable behavior witnessed inside the Boleyn Ground and will take the strongest possible action against anyone found responsible , including life bans . West Ham , Millwall and the Football Association denounce violence .
Violence marred the English League Cup tie between West Ham and Chelsea . A 44-year - old man was stabbed in the back and police made 13 arrests . Metropolitan Police are now investigating evidence of violence and offenders . West Ham , Millwall and the Football Association denounce violence .