It is possible that this case is the same as Sacha Vallée
Sasha is a nickname for Alexander, and the details are similar (4 years old, beaten to death by mother's boyfriend).
I suspect that this was just reported to the russian authoritie
It looks like the same case. But I find it strange for the dates. Sacha was murdered in 2002 and the trial was done in 2004. In the case of Alex, it was reported on Twitter in 2001.
Is it possible the case was reported almost 10 years later to Russia?
It is Sacha Vallee.
The tweet included Eric Greiner's name and referred to the boy as "Sasha" not Alex, as some translations listed it.
Thanks for the update. The articles originally listed with this entry have been merged with the ones about Sasha Vallée.