I am helping a friend research her roots. Her grandmother escaped Siberia in about 1920, leaving the rest of the large family of Rublovs behind in Ulan Ude where Pavel Rublov owned a tea importing company. The family had wealth so it is likely they may have run into trouble with the Bolsheviks. Is there any way to determine what happened to Pavel and Ludmilla Rublov and the other children?
Researching the roots is one thing, if you want to find what happened with the ancestors is another.
For the genealogical research, it would be helpful to know where exactly Pavel and Ludmila lived. Then you can start from the local archives, for Ulan Ude it would be State Archive of Buryat Republic - http://gbu-garb.ru
If you don't know Russian, it would be much easier to hire a local researcher for that. Even if you know Russian, it would be helpful, because it will greatly accelerate the process. You can find birth/death/marriage records before 1917, in some instances before 1920s, in the local archive. For newer records you'd need to go (or send a request by mail) to the local ZAGS (civil registration office) archive, which usually requires some proof of ancestry with the people you do research about. Again, it's easier and much faster to do in person. Unfortunately, most of the local archives in Russia are not digitized, so you can't just look up that information on some web site.
If you want to know what happened to particular people, it's harder. It could require detective-like work. Some pieces of information could be found in archives as well.
When/if you find information about other children of Pavel/Ludmila, you can search in public WWII archives for example, there is some chance to find something there. Those archives are available on internet. If you know where they lived, it's possible to research what happened with that particular place over time, does it exist or not, who lived there and when etc. If you're lucky and those people lived in Ulan Ude all their life, you could find death records in the same civil registration archive. If not, it will require a lot more work most likely.