Dutch police have arrested four more suspects in their investigation into the attack on a volunteer linesman who died a day after players on a youth team assaulted him following a match.
The arrests on Tuesday bring to eight the number of suspects in custody in the case - seven of them teenagers.
Police say in a statement they have arrested three teenagers and a 50-year-old man, the first adult to be detained in the case, all from Amsterdam.
Linesman Richard Nieuwenhuizen's death just over a week ago sparked national soul-searching about the rising tide of violence on and around Dutch sports and how to rein it in.
Some 12,000 people attended a silent march Sunday to commemorate Nieuwenhuizen.