A reward of up to �20,000 has been offered to help catch the killers of 16-year-old Ailton Campos De Oliveria who was stabbed to death in East Ham on July 4.

Detectives hope the cash for information leading to the identification, arrest and prosecution of those responsible for stabbing the East Ham teenager several times including inflicting a fatal wound to the chest.

Police particularly want to speak to seven people captured on CCTV in the area at the time who may have seen the suspects fleeing the scene at around 1.15am.

So far 20 youths aged mailny aged between 15 and 18 years old have been arrested in connection with the incident, with 12 bailed to reappear at an east London police station at the end of this month and in December, but no charges have been brought.

The St Bonaventure’s student was confronted by a group of black teenagers in Boundary Lane.

He was pulled from his bicycle, and chased into Denbigh Road by the gang, some of who were on bikes.

An eyewitness, who did not want to be named, told the Recorder Mr De Oliveria was pinned down and beaten around the head in the garden in front of one of the houses with one attacker wielding a baseball bat.

He was also stabbed in his leg and back.

The teenager from East Ham died two days later in The Royal London Hospital, Whitechapel.

Detective Chief Inspector Simon Moring, of the Met’s Homicide and Serious Crime Command, said: “We hope that this substantial reward will encourage anyone with information about Ailton’s murder to come forward. A group of young people targeted Ailton, stole his bike and attacked him in the middle of the street.

“Despite the greatest efforts by medical staff Ailton died and his family and friends are left devastated. Someone knows the group responsible and we urge them to think about Ailton and his family and come forward to help us.”

Officers are appealing for anyone who may have been offered Mr De Oliveira’s bike or mobile phone, both of which were stolen before he was killed, to come forward.

The teenage was riding the black ‘hardrock’ bike when he was attacked.

It had the brand Specialized in red letters across the body and distinctive customised white front shock absorbers,

His Blackberry Curve mobile phone was stolen by his attackers.

Anyone with information is asked to call the incident room on 020 8345 4142 or call Crimestoppers anonymously on 0800 555 111.