Detectives hunting the killer of Karen Reed, 33, said yesterday that the information came from a friend of the dead woman, who had been standing behind her when the gunman fired at least four bullets into her body.
But the victim's sister, Alison Ponting, whose husband was jailed for life for murdering two high- ranking officials of the self-proclaimed Chechen republic, part of the former Soviet Union, echoed police fears that her death was the result of their being related.
Last night, Ms Ponting, 31, a producer with the BBC World Service Russian section, was still being kept at a secret address under armed guard and police were preparing to take similar precautions for her parents, David and Iris, who were flying back to Britain. However, detectives have failed to contact Mrs Reed's estranged husband, Julian. It is thought that he may be out of the country.
About 40 police officers again spent the whole day on the Barnesbury Farm estate in Woking, Surrey, conducting house-to-house inquiries and carrying out a finger-tip search of Mrs Reed's house in the search for clues to Saturday night's doorstep killing.
Officers also travelled to Long Lartin prison, Hereford and Worcester, to interview Ms Ponting's husband, Gagic Ter-Ogannisyan, who is serving a double life sentence for killing Ruslan and Nazerbeck Outsiev, the prime minister of the Chechen republic, and his brother, in London in February last year.
In the light of the evidence of the woman at the house at the time of the killing, Det Supt John Stewardson, leading the investigation, has ruled out the assassin as being of east European origin.
The woman, a family friend who police declined to name, told them that the killer said 'one or two words' to Mrs Reed when she opened the door. 'They were just a few mere introductory words,' he said. 'The person had no trace of a foreign accent.'
But, in a handwritten statement issued through Surrey Police, Ms Ponting revealed that she believed the gunman might have been hired to avenge the killings in which her husband was involved. 'I am deeply shocked and distraught by the death of my sister, Karen, who was murdered so horrifically simply because of her relationship to me. She was a wonderful, warm, understanding person, who can never be replaced and who will be forever missed by everyone who knew her.'
Her statement contained a plea for help in catching the killer. 'I appeal to anyone who is able to help the police in any way, whether they saw something, heard something or think they know something, to contact Woking police.'