The mother, 44, and her six- year-old daughter were bludgeoned to death a year ago. The second daughter Josie, 10, was left for dead by the attacker, who also killed their dog. The assault happened on a country footpath near the family's home in Chillenden, Kent.
Police believe a hammer was used. Josie barely survived but gradually regained her power of speech and began to remember details of what happened.
She and her father, Shaun Russell, now live in Wales, where the family lived before moving to Kent.
The Forensic Science Service has developed a method of obtaining mitochondrial DNA from dead hair and bones. It was used to identify the bones of the Tsar's family four years ago. The DNA is inherited through the mother and does not degrade like chromosomal DNA currently obtained from living cells such as blood and saliva samples. A hair sample without roots was recovered from the murder scene.
Mitochondrial DNA is not as accurate as the current system but could help eliminate suspects and provide additional evidence against the alleged killer. The breakthrough in the DNA sampling is expected to be announced today.
Doctor Janet Thompson, chief executive of the Forensic Science Service, said yesterday that the new DNA technique was capable of providing a vital piece of evidence in the case, as it cannot be relied upon on its own.Reuse content