A gang member has been sentenced to life imprisonment for knifing a teenager to death in a stairwell.

Kai Shannon, 20, of Elmore Street, Canonbury, was sentenced to a minimum term of 18 years behind bars after being found guilty of murdering 18-year-old Wahab Zaaki in Walthamstow.

He appeared alongside Abubaker Alwai, 20, of Essex Road South, Leytonstone, who was convicted of manslaughter. Both defendants were also found guilty of GBH after knifing one of Mr Zaaki’s friends as he tried to prevent the attack.

During the trial it was revealed that Shannon and Alawi were known to the victim as well as a group called the “DM Crew”.

Acting Det Ch Insp Steve Meechan, who led the investigation from the Met’s Homicide and Serious Crime Command, said: “This was a callous, cowardly and premeditated attack upon the young victim, by those he trusted as his friends. The motive for the attack remains unclear, the suggestion being a disagreement over an insignificant sum of money.

“It has taken three years to bring those responsible to justice. These defendants instilled within their peers a reluctance to assist police.”

Mr Zaaki’s father Amin Zaaki said outside the Old Bailey that the family was “very happy” with the sentences given but spoke of his anger that his son’s killers had refused to tell the family the truth about the reasons behind the attack in March 2009. He added: “We cannot describe the pain we are feeling.”

Shannon will serve a minimum of 18 years for murder and a further eight years for GBH, to run concurrently.

Alawi was sentenced to nine years in a young offenders institute for manslaughter and a further three years for GBH, to run concurrently.