Det Supt Paul Durham, leading the inquiry, said: “We're looking at the possibility of mistaken identity, a drugs debt or a domestic type thing.”

He said the a line of inquiry that it was a drug debt was not a suggestion that the serviceman was involved in drugs, but that it might be a case of mistaken identity.

One of the suspects tried to grab the airman who was out running in civilian clothes around a mile from RAF Marham near Kings Lynn.