[Nicky91]

official statement from AZ club website

'Pitch black evening'
While everyone hoped for a historic European match, it turned into a pitch black evening due to the events occurring at the referee’s final whistle. It turned into a night to reflect on with shame. Not because of the football game played, but because of the behaviour of some visitors. Unfortunately, we cannot use the word ‘supporters’ for these people.

What happened is beyond all bounds. The club again sincerely apologises to West Ham United and the thousands of well minded AZ supporters who have also been inconvenienced by the misconduct.

In the coming period AZ will – together with the police, Public Prosecution Service, and Alkmaar’s municipality – evaluate exactly what happened, how it could have happened and what needs to be improved from now on. It is clear that things need to be improved. Part of the evaluation is a thorough review of all available footage so that appropriate consequences may follow for those responsible for this outrageous behavior.

AZ is a civilised club where sportsmanship and norms and values are paramount. The club will do everything possible, together with the authorities involved, to identify these persons and to take appropriate measures.

https://www.az.nl/nl/nieuws/statement-inktzwarte-avond