Detectives investigating the murder of Luke Fitzpatrick have arrested a fourth man.
A 23-year-man was arrested on suspicion of murder at an address in Wembley on Monday.
Police continue to appeal for witnesses and information after the murder in Dollis Hill on Saturday night following the Champions League final.
Luke Fitzpatrick, 25, died at the scene. A post-mortem held at Northwick Park Hospital on Sunday gave the cause of death as stab wounds.
His father Bernard Fitzpatrick, 56, remains in hospital where his condition is serious but stable.
Three men, two aged 17, another aged 31, who were previously arrested have been bailed to return pending further investigation.