The man found guilty of the hammer murders of Lin and Megan Russell in Kent could win a new appeal over his convictions, it has been revealed.
Stone is serving three life sentences for murder and attempted murder
The Criminal Cases Review Commission (CCRC) is assessing if there is "any new evidence or anything to cast doubt on the safety of his convictions".
Michael Stone was originally convicted of the 1996 killings in 1998 and then again at a retrial three years later.
He has also appealed on a second occasion but that was rejected in 2005.
A CCRC spokeswoman said on Sunday: "His [Stone's] case file has been allocated to a case review manager.
"If there is any doubt over his convictions, then his case will be referred to the Court of Appeal.
"We will look to consider whether there was anything that wasn't considered at trial or appeal."
Josie Russell survived and now lives with her father in Wales
The spokeswoman added that the timescale for examining the case could be anything from a "few months to years".
Stone's solicitor Paul Bacon said: "We have had a meeting with the CCRC and they are actively re-investigating Michael Stone's case.
"They will look at all aspects of the case including the confession and the forensic evidence, taking into account the advances in DNA technology."
Stone is serving at least 25 years for murdering Dr Russell and her daughter Megan, as well as for the attempted murder of her other daughter Josie.
She survived an attack as the family walked along a country lane in Chillenden, near Canterbury, in July 1996.
Stone won a retrial when his convictions were quashed in February 2001, but he was again found guilty later that year.
A second appeal was turned down in 2005.