Someone knows what happened that evening and I am urging them not to remain silent but to come and speak to us. Your information will be treated in the strictest of confidence.
Likewise I am directly appealing to the family members and friends of those believed to be involved - if you have slightest indication the person you know may have been involved in this incident I encourage you to get them to hand themselves into the police.
Failing to do so will result in my officers pursuing them.
More top news
Combined strike action looks set to bring parts of the Tube and rail network to a halt this week.
Kenny Sansom has been left penniless and feeling worthless after decades of alcoholism.
A close associate of hate preacher Anjem Choudary has been jailed for knocking a boy unconscious because he was cuddling his girlfriend.