On the face of it, Maria Romanova's legal application to Russian prosecutors might seem straightforward. As the self-described head of the surviving family of Nicholas II, Russia's last czar, Ms. Romanova wants rehabilitation for her ancestors, according to her lawyer. Under Russian law, this would mean a formal admission that Nicholas II was unjustly killed along with his wife, children and attendants after revolution swept away Russia's monarchy.

Boris Yeltsin went far beyond such recognition during his term as Russian president, apologizing for the killings and describing the incident as one of the most shameful chapters of Russian history. The Russian Orthodox Church went even further, canonizing the family as minor saints.

But the country's legal system has never recognized that anything wrong happened on the night of July 16 and 17, 1918, when Bolsheviks lined up the royal family in the basement of a house in Yekaterinburg and shot them to death.

"This is the last step," said German Lukyanov, the family lawyer. "Why must this be done? Russia needs it, to finally close this disgraceful, bloody chapter of Russian history."

Closing the case of Russia's last czar might prove difficult, however. Many details about the incident are passionately disputed, and Ms. Romanova's application last month has shaken the dust off old debates that some Russians would rather leave undisturbed.

"The question of the czars is implied in the question of whether communism was a good idea," said Ivan Plotnikov, 80, a retired colonel and professor of history in Yekaterinburg.

"And this is a question some people still ask themselves."

The emotions run deepest in this industrial city on the eastern edge of Siberia, about 1,600 kilometres east of Moscow.

During interviews, some historians grew red-faced, raised their voices and even foamed at the mouth when arguing about what happened here almost a century ago.

The downfall of the royal Romanov family started in 1917, when discontent with the monarchy broke out into riots on the streets of St. Petersburg. The government resigned and parliament asked the emperor to give up his throne. Nicholas obeyed, and was eventually forced into house arrest in Yekaterinburg.

As civil war raged in the summer of 1918, opponents of the Bolsheviks approached the city and Bolshevik leaders decided to kill the czar to prevent the advancing army from saving him.

But questions about the killings almost outnumber the facts: Did Vladimir Lenin himself give the execution order, as many believe? Were the remains buried in a shallow grave, as some say, or have the real bodies never been discovered?

The absence of any court records or written execution order could make it difficult to apply the Russian law on rehabilitation, some experts say, because the Prosecutor-General may decide there isn't any decision that could be overturned.

The Russian government held a burial ceremony in St. Petersburg in 1998 for remains of the czar, his wife, three of his children and four attendants, after a geologist claimed the discovery of their bodies outside Yekaterinburg.

But the patriarch of the Russian Orthodox Church boycotted the event because of doubts about the authenticity of the bones, and those questions grew stronger after DNA analysis by Japanese researchers contradicted the results of several other DNA tests.