Gunfire was reported at around 12.30am on Sunday after around 50 to 100 people gathered in and around Cheney Row Park. Two men later arrived at a local hospital, one of whom died of gunshot injuries.
The second man, in his 30s, was arrested after suffering stab wounds in the same incident. He was taken into custody after being discharged from hospital.
Mr Brown lived in Waltham Forest, where the incident occurred. Witnesses have been urged to remember the victim’s ‘grieving mother and father’ and help police with their inquiries.
Detective Chief Inspector Kelly Allen from the Metropolitan Police, who is leading the investigation, said her ‘heart goes out to the family of Sam, who has lost his life in this reckless act of violence’.
She continued: ‘I believe there were 50 to 100 people gathered in and around Cheney Row Park at the time of the shooting with music playing.
‘I urgently need to speak with everyone who was at that event – even if you do not believe you saw anything significant, you need to come forward.
‘There will have been footage and images captured at the event, and we need to see these. ‘Please ensure that all such material is saved – we will provide a link for it to be uploaded shortly.
‘To anyone considering whether or not to come forward to police, I ask you to put yourself in the position of the victim’s grieving mother and father this morning. They deserve answers.’