The 15-year-old boy shot dead in a park in west London on Sunday has been named.

Rene Graham was killed in Emslie Horniman’s Pleasance Park in Ladbroke Grove, west London, at about 7.20pm on Sunday, the Metropolitan Police said.

Four men, two aged 21 and the others aged 20 and 25, have been arrested on suspicion of murder and are in custody, and a crime scene remains in place.

Forensic officers were seen searching the area and taking photographs on Monday.

At the time of the attack, it is believed more than a thousand people were attending the annual Park Lime event, organised by the Caribbean Music Association, which was billed as a “family fun day” featuring live music, games and face painting.

Detective Chief Superintendent Christina Jessah said: “This investigation is at an early stage and we are keeping an open mind as to the motive.

“It will take us some time to establish the facts and this will be our priority in the coming days.

“We are keen to speak to other witnesses who were in the area at the time of the shooting.

“There was an event taking place and it’s possible people may have been taking photos or filming.

“Please check to see if you have captured anything that may help detectives.”

Police earlier incorrectly said six people had been arrested as part of the investigation.

Father Damian Ryan, 43, a priest at a church bordering the park, estimated that more than 1,000 people were at Sunday’s event and were “spilling over” on to the nearby streets.

He said: “Several months ago there had been a murder, a couple of hundred yards away someone was murdered.

“I’ve only been here two years, but other parishioners, people in the community, are saying this is not completely abnormal.”

Elizabeth Campbell, leader of Royal Borough of Kensington and Chelsea Council, said the shooting was “absolutely horrific and just awful for the family”.

When asked what the council is doing to reduce violence in the area, Ms Campbell said: “We do huge amounts.

“We have detached outreach teams working with the young, we have a huge amount of youth clubs, we have outstanding social work, so we do absolutely everything we can on our side as the council.”

Anyone with information has been asked to call 101 or message @MetCC on X, formerly Twitter, providing the reference 6343/21JUL, while information can also be provided anonymously to the independent charity Crimestoppers on 0800 555 111.