When trying to reconnect with his estranged father, the illegitimate son of a Russian Mafiosi learns that his unrepentant father ordered the hit that killed his mother. Unable to get justice by legal means, he build his own criminal empire to destroy his father.

I like it. Much better than the original attempt. And I like Richiev's rewrite too. Now get going on the writing (says she who is stuck with her own stuff)......

Good re-write, Richiev. It does what a logline is supposed to do: describe the essence of the story, no more, no less.

Yeah, I thought this logine explained more and just needed shortened a bit.

Basically I cut: "Unable to get justice by legal means" because I didn't think it was needed.

And I cut out: "When trying to reconnect with his estranged father" because the incident that actually get's the story going is finding out his father ordered the hit."

In my original idea, I referenced the Italian MafiA, but the the Italian mafia had been over done. So I switched to the Russian mob, I may have to relocate my story near little Odessa. Still doing research on the subject.
Your version is definitely shorter than mine, but people asked me so many questions in my previous attempt that I have tried to cram as much as possible information in the logline.
Maybe too much.

"After discovering his estranged mafiosi father ordered the hit that killed his mother, an illegitimate son builds his own criminal empire to extract revenge."