In The Bourne Supremacy, the Russian politician Bourne is linked to killing is Vladimir Neski. Neski had been investigating the theft of $20 million from a Russian oil deal when he and his wife died in Berlin in an apparent murder-suicide.
The Neski files become central to the film’s conspiracy. CIA Deputy Director Pamela Landy believes the documents may reveal who stole the money, while former Treadstone operative Jason Bourne becomes the convenient suspect. Russian agent Kirill kills a CIA agent and a source, steals the files and money, and plants Bourne’s fingerprints to frame him.
Bourne gradually reconstructs what happened and discovers that the conspiracy reaches back to CIA corruption and his own past as an assassin. His investigation eventually leads him to Irena Neski, the politician’s daughter, in Moscow. Rather than kill her, Bourne tells her the truth about her parents’ deaths.
The name is sometimes confused with Yuri Gretkov, the Russian businessman behind the operation, or Kirill, the operative who carries out the attack. Neither is the politician named in the question.