Two key witnesses were running about the area

Adam Regis, nephew of Olympic sprinter John Regis, was stabbed in Plaistow, east London, after a night out with friends at the cinema in March.

The camera caught two young men getting into a Volkswagen Scirocco car minutes after the stabbing.

Adam, of Plaistow, east London, died of stab wounds to the chest and abdomen.

'Good lad'

Appealing for information about the killers at a press conference at West Ham Football Club, Det Ch Insp Mathew Horne said, the killers probably used a knife or a small sword with a 20cm-long blade.

The teenager was probably stabbed without warning from behind and the blade penetrated his hand and entered his heart, he added.

Adam Regis was stabbed to death near the football ground

A CCTV camera also captured a gang of five circling the Upton Park area in the car.

Police are also keen to trace two other men who were seen running at about 2130BST in New City Road, close to the murder scene at the junction of Boundary Road and Kingsland Road in Plaistow.

"It is difficult to see why anyone would want to kill Adam because there is no reason. He was a good lad," Det Ch Insp Horne added.

West Ham Football star Bobby Zamora also joined the appeal.

"Growing up in east London, and still living here, this has come as a shock to me... and this has shocked the community," he said.

The teenager's mother, Kristina Caesar, who was also present, said: "He would not hurt anybody. He would look after everyone. I miss him so much at home."

Officers have announced a reward of �20,000 for information leading to the conviction of the killers.