Mystery surrounds the precise reason why an 18-year-old Canning Town boy chose to pick an argument with 27-year-old Ade Afariogun in an east London park.

But the cause was ultimately inconsequential in the face of the “cold-blooded” outcome.

Ade was left with a 12cm knife wound in his abdomen. He hung on for nearly four days at an east London hospital but died from his wounds.

The attack took place in broad daylight – the afternoon of Friday, January 29 – and the victim was with three female friends.

Kaleb Amponsah, 18, of Robertson Road, rode past the group several times, staring aggressively at Ade but saying nothing.

As the group was leaving Plaistow Park, Amponsah drew his bike in front of them and started an argument with Ade that led to a scuffle.

The two exchanged punches, with one of the females making a futile attempt to intervene.

Amponsah then pulled a large blade from his waistband and stabbed Ade in the stomach twice. He fled the scene, dumping his bike and his mobile phone, and leaving his victim for dead.

Ade was taken to the Royal London Hospital but the best efforts of medical staff were unable to help him.

The attacker made a few attempts to evade police. He went to a friend’s house a few streets from the murder scene but left quickly, returning home to change his clothes. He then hid out at another friend’s house for the afternoon.

All the while police were using DNA from his phone and bike to identify the killer and, five days after Ade died, Amponsah was arrested at his home where police found clothing and a large knife hidden in his mattress.

On Thursday, July 28, Amponsah was found guilty of murder at the Old Bailey. He will be sentenced in the next few weeks.

Det Sgt Perry Benton, from the Homicide and Major Crime Command, said: “Five months after the original charge, Amponsah admitted being responsible for the fatal stabbing but claimed he had acted in self-defence after the victim attacked him.

“Thankfully the jury saw through this unlikely scenario, recognising this for the needless and cold-blooded murder it was.

“The park where this took place is well used by a wide range of residents and the local community should feel reassured that this type of attack is an extremely rare occurrence.

“Ade was in the park with friends when he was killed for reasons that we have been unable to ascertain. He was well loved by his family and friends, who miss him very much.”

In a statement read to the court, the victim's stepfather, Kay Oluwa, said how the incident had "devastated" the family.