A heated scientific dispute over the genetic identification of the remains of the Russian royal family may come to a head at an international conference next week.
A group led by Alec Knight, a senior scientist at Stanford University's Laboratory of Anthropological Sciences, has raised doubts about the original research.
This original work, which was led by Peter Gill, a British Home Office forensic scientist, identified nine bodies exhumed from a pit in Ekaterinburg as Tsar Nicholas II, the last ruler of imperial Russia, and members of his Romanov family and household, all executed by the Bolsheviks in 1918.
Dr Knight and his team, which includes scientists from the Vavilov Institute of General Genetics in Moscow and the Los Alamos National Laboratory in the US, unsuccessfully attempted to replicate the tests using mitochondrial DNA from a relic of the sister of the Tsar's wife.
Their analysis of the original research led them to argue that there had been "gross violations of forensic investigative norms and factual inconsistencies" and that the Ekaterinburg samples had been contaminated with modern genetic material.
They concluded that the skeletons recovered from the pit were likely to be unknown victims of the Russian Civil War.
The revisionist thesis will be presented at next week's International Ancient DNA Conference in Brisbane, Australia. Dr Knight, who will not attend in person, admitted that the presentation would not be defended despite the presence of members of the original team at the meeting.
Thomas Parsons, chief scientist at the US Armed Forces DNA Identification Laboratory, who will address the conference, said Dr Knight's arguments were not convincing.
He argued that a battery of different tests, which included analysis of a DNA sample collected from Prince Philip, who was related to the Tsar's family, led to the conclusion that the remains were indeed those of the Romanovs.
"The DNA results speak for themselves: when taken together, it is a fantastically unrealistic suggestion that these results could be the result of contamination, either random due to error, or intentional due to a vast conspiracy of all-knowing evil scientists," he said.