Aleksandr Osadchuk was one of the 12 Russian intelligence officers indicted by the special counsel in July of 2018.
All of the indicted individuals worked for Russian military intelligence agency GRU. They were accused of interfering in the 2016 presidential election by stealing and releasing documents from the DNC and DCCC through Guccifer 2.0 and DNCLeaks.
Osadchuk was a Colonel in the Russian military and commanding officer of Unit 74455 which assisted in the release of stolen documents through the DCLeaks and Guccifer 2.0 personas, the promotion of those releases, and the publication of anti-Clinton content on social media accounts operated by the GRU.
The constitution of Russia forbids the extradition of Russian citizens to face trial in other countries,so it’s unlikely any of these people will be brought to justice.