Police say Ayub Khan may no longer be in the UK

They are asking for help from the public in tracing Ayub Khan, 21, from the Forest Gate area.

Amarjit Singh, 52, and his nephew Rajinder Singh, 35, of Chigwell, Essex, were shot with a machine gun near the hotel they owned in Forest Gate.

A �10,000 reward is being offered for information leading to a conviction.

Police believe the killings could have followed a row over parking.

Shortly before the shootings, Amarjit Singh's blue Renault van had been attacked and damaged by three men described as being of Asian appearance.

The Singhs were shot dead apparently after a row over parking

Detectives are also keen to trace two other men.

Detective Superintendent Maureen Boyle, who is leading the investigation, said: "Amarjit Singh and his nephew Rajinder were simply going about their work when they were callously murdered.

"They posed no threat to anyone, making these completely senseless killings.

"As part of our investigation, we would now like to speak to Ayub Khan and would urge anyone who knows his whereabouts or who may have seen a man matching his description to contact us immediately."

Amarjit's brother Gurdeep Singh told BBC London the family was devastated.

"Amarjit and Rajinder were the pillars of my family. We have lots of loving memories.

"Amarjit was a great brother, a great family member and Rajinder was also a very respectful, loving person."

Four people were arrested last year in connection with the case.

Two were released and two others bailed to return to an east London police station in June.