The International Criminal Police Organization (Interpol) listed Russian citizen Ruslan Mukhudinov wanted on suspicion of the murder of Boris Nemtsov.
Mukhudinov, 29, is wanted on charges of murder and illegal firearms trafficking, Interpol's website states.
Nemtsov, who occupied a number of senior positions in the Russian government in the 1990s, and was an active opposition politician in the 2000s, was gunned down in downtown Moscow on February 27, 2015.
Mukhudinov, the alleged mastermind, has been arrested in absentia and is believed to be in the United Arab Emirates. He is among six suspects of playing a role in Nemtsov's murder.