The bodies of Czar Nicholas II and his wife Alexandra have been exhumed as Russian authorities reopen an investigation into the family's murder.
The country's last Romanov royal couple were killed by Bolshevik revolutionaries in 1918, together with their daughters Olga, Tatiana, Maria and Anastasia, and their son Alexei.
On Wednesday investigators took DNA samples from Nicholas and Alexandra to confirm the identification of Alexei's and Maria's remains.
Nicholas, his wife and three of their daughters were found in a mass grave in the Urals in 1991 and identified by DNA testing in 1998. The remains thought to be those of Alexei and Maria were not found until 2007 and they were found some distance away. They have been kept ever since in a state repository awaiting burial.
Church calls for identity confirmation
The Russian Orthodox Church called for the parents' bodies to be exhumed and re-examined so that their DNA can be compared to that of Alexei and Maria. Then, if their DNA matches, they can be buried along with the rest of the family.
Investigators will also compare the brother and sister's DNA against bloodstains on the uniform of their great-grandfather, Emperor Alexander II, who was killed in a bombing by radicals in St Petersburg in 1881.
The Royal couple were exhumed from their tomb in St Petersburg's Peter and Paul Cathedral. Nicholas, his family and four servants were executed by firing squad in July 1918 at a house in Yekaterinburg, and their bodies were thrown into a mineshaft.