Police were called to Brent River Park, Wembley at 7.05pm on Sunday, 8 July by London Ambulance Service (LAS) following reports of a man found unresponsive.
Officers and LAS attended and found a man with serious head injuries. He was pronounced dead at the scene.
His next of kin have been informed.
A post-mortem examination will take place in due course. Formal identification awaits.
A crime scene remains in place. Police in Brent continue to deal.
The Homicide and Major Crime Command has been informed.
Enquiries into the full circumstances continue.
Inspector Sammi Elsituri from Brent said: “This incident will no doubt alarm and shock those in the local community especially coming so soon after a fatal shooting in Wembley on Friday night.
“My officers are busy at the crime scene and will be knocking on doors and reviewing local CCTV footage to help build a clearer picture of what has taken place.
“Specialist police resources are in the area working to help solve this crime and provide reassurance to the public. Police officers will be on hand to speak to locals about concerns they have.
“We will work relentlessly – day and night – to identify and pursue the culprit(s), bring them to justice, and take weapons off the streets to keep our communities safe.
“I would urge anyone with information, however small it may seem, to contact investigators to help them build a clearer understanding of what has unfolded and who is involved.”
Anyone with information concerning this incident is urged to call police on 101 quoting CAD 6884/7 July or Crimestoppers anonymously via 0800 555 111