MOSCOW, Russia (CNN) -- It was 90 years ago Thursday that Russia's last royal family was executed -- but this year's anniversary comes with scientific proof ending years of speculation that some of the Romanovs managed to survive.
Medical, forensic and ballistic tests conducted in several U.S., Russian and Austrian laboratories identified bone and tooth fragments unearthed last summer as belonging to two missing children of Czar Nicholas II.
Chemically damaged and burnt remains found outside the city of Yekaterinburg in 2007 are those of Crown Prince Alexei, 13, the last emperor's only son and heir to the throne, and his sister Grand Duchess Maria, about 19, according to the Investigative Committee of the Russian Prosecutor General's Office.
"The remains that were found belong to Alexei and Maria. We can say that with certainty," Vladimir Solovyov, a senior investigator with the committee, told a news conference Wednesday.
Bolsheviks executed the czar's family and a few servants July 17, 1918 in the basement of a home in Yekaterinburg. But the two children's bodies were missing for decades, leading to persistent hopes among royal supporters that one or both of them had survived.
Although the investigative committee stated the remains belong to Alexei and Maria, its report said scientists will nonetheless continue comparing DNA from the remains to that of the living Romanovs.
"We have to be really careful with release of the information, because previously too many unnecessary disputes happened regarding the DNA data and genetics data," said Evgeny Rogaev, a czar family DNA researcher for over a decade.
"We have to complete our analysis. There are some new possibilities, new findings -- some findings of a blood sample, for example, in museum storage in St. Petersburg recently, of Nicholas II. It is a potential future study."
Since last weekend, Russian royalists have been commemorating the killings of the last members of a centuries-long imperial dynasty by singing, praying and joining religious processions.
Grand Duchess Maria of Russia, the head of the Russian Imperial House and Nicholas' great-grandniece, has come from Madrid to visit places related to the royal saga and meet Russian Orthodox Church representatives and relatives.
The ceremonies culminated Thursday in Yekaterinburg, in the Ural Mountains about 880 miles (1,400 kilometers) outside Moscow, at a cathedral built on the spot where the Romanov family was killed.
Both sets of remains were found around that area. The so-called second burial spot is about 230 feet (70 meters) away from the first grave discovered in 1991, where bone fragments of Nicholas II, his wife Alexandra and their three daughters were exhumed.
Those bodies were solemnly buried in 1998 in a cathedral in St. Petersburg among other Russian royalty crypts. The Russian Orthodox Church canonized Nicholas and his family two years later.
The two newly identified bodies, however, remain unrecognized by the church. The Russian Imperial House of Romanov announced they would follow the Russian Orthodox Church's opinion and therefore also refuse to recognize the remains as Emperor Nicholas's offspring.
"Of course, as a head of the Imperial House, nothing would please me more than (if) these remains would finally be those that we've been looking for so many years," Grand Duchess Maria told CNN.
"But, unfortunately, some dark forces around the country have popped out some doubts about whether they really are. That's why the church and the patriarch have asked to have questions answered about previous remains and these. But unfortunately these questions haven't been answered."
Grand Duchess Maria of Russia also recently filed two new court appeals in a long-running battle to get the Russian government to recognize the last czar's family as political repression victims and to recall the death sentences issued by the Soviet government in 1918, calling them a symbolic beginning to the Soviet mass repressions.
"It is pleasant for somebody who has a relative or a grandfather or father who died, and the whole country believed him to be an enemy of people, that finally it be proved that it's not that, and you can carry your name with pride again," she said.