The Bolshevik Revolution saw the end of the Romanov Dynasty when Bolsheviks killed Czar Nicholas II, his wife and children.

On 17 July, 1918, the family was lined up in a cellar of a house in Yekaterinburg along with four royal staff members, as if for a photograph. A Bolshevik firing squad walked in and killed Tsar Nicholas II, Alexandra, their four daughters - grand duchesses Anastasia, Maria, Olga and Tatiana - and their son, the Tsarevich Alexei. Those who did not die immediately were bayonetted. The remains were doused with acid and buried in an unmarked pit, until they were discovered by amateur researchers in 1979.

The bodies of Nicholas, Alexandra, and three of their daughters were exhumed, tested and reburied in St. Petersburg on July 17, 1998, the 80th anniversary of their deaths.

But the remains of Alexei, Nicholas and Alexandra's son and heir, and his sister Maria were not found, leading many to believe that the siblings had escaped the slaughter.

The year 2007 saw the discovery of two more sets of remains at a nearby site. DNA tests confirmed the remains to be genuine and belonging to Alexei and Maria.

But the Russian Orthodox Church, which had canonized the family members in 2000 has demanded the investigation into the 1918 murders be reopened, before it allows the remaining family members to be buried at St. Petersburg. "The leadership of the Investigative Committee has decided to resume the preliminary investigation to conduct additional studies and investigative steps," Vladimir Markin, a spokesman for the Russian Investigative Committee told Interfax, reports USA Today.

The exhumation of the bodies, along with collection of tissue samples of Romanov family members buried in Jerusalem, and blood samples from the czar's grandfather, Alexander II, who was assassinated in a bomb attack in 1881 have been collected to satisfy the church. A burial is expected later this year.

"The exhumation was done in the presence of representatives of the Russian Orthodox Church. The necessary samples were taken from the remains of Nicholas II and Empress Alexandra Fyodorovna," Vladimir Solovyov, the head of the investigation team, told TASS, a state-owned Russian news agency, reports The Telegraph.

"Not all aspects of the imperial family's murder were explained in the case, and not all the Russian Orthodox Church's questions were answered fully and clearly. The grand duchess hopes that the examination of the Yekaterinburg remains will be scientific... The truth must be established in this case, with an answer to the main question: whose are these remains?" said German Lukyanov, a lawyer for Grand Duchess Maria Vladimirovna, a descendant of the murdered Romanovs, who says she supports the investigation, according to the BBC.