The men owned several businesses in the area

Officers investigating the deaths of Amarjit Singh, 52, and his nephew Raginder Singh, 35, on Saturday, were back in Forest Gate, east London, hoping to jog witnesses' memories.

They are still not sure why the two men were killed, near the hotel they owned.

They believe it could have followed a row over parking.

The property developers are thought to have been shot after blocking in two other cars - a blue or green Honda Civic hatchback and a blue Volkswagen Golf in Atherton Mews.

Detective Superintendent Maureen Boyle said: "These two vehicles had been beeping horns, trying to attract attention because they were blocked in,"

This is a shocking and senseless killing which happened in broad daylight. Detective Superintendent Maureen Boyle

"Amarjit Singh eventually came out and moved the vehicles. The Honda drove off.

"Before the Volkswagen drove off, there was a heated argument between Rajinder Singh and the driver of that blue Volkswagen.

"We are clearly anxious to talk to the occupants of both these vehicles."

Posters and leaflets were handed out around the area on Friday as police looked for more witnesses to the murder.

Devastated family

Police are also trying to trace the driver of a black BMW which braked to avoid one of the suspects.

DS Boyle believes the car may have made contact with the suspect, and could still carry forensic evidence.

It is thought the weapon used to kill the Singhs, from Chigwell in Essex, may have been pointed at two pedestrians in nearby Abbey Street, Plaistow, earlier that day.

A 23-year-old man arrested in connection with the incident has since been released on bail.

DS Boyle added: "This is a shocking and senseless killing which happened in broad daylight.

"The Singh family have been left devastated by the events of last Friday and we are determined to catch those responsible."