RIA Novosti reported two men on the international wanted list were arrested and detained in February following an explosion in their apartment. A third man was killed. All of them were trying to concoct home-made explosives.
After the detainees, Ilya Pyanzin and Adam Osmayev, were arrested in the Ukrainian port city of Odessa, they confessed to having been hired by Umarov to perpetrate an attack on Putin. They also confessed to plotting murder against Chechen leader Ramzan Kadyrov, but neither plot allegedly got past the planning stage.
Umarov, the self-named Emir of the "Caucasus Emirate," claimed responsibility for the 2009 bombing of a train going from Moscow to St. Petersburg that killed 26 people as well as 2010 suicide attacks on the Moscow subway in which 40 people died and last January's bombing of Moscow's airport that killed 37 people.
Although a Moscow court issued an extradition order for Pyanzin and Osmayev to come from Ukraine, one wasn't issued for Umarov because the Russian Federal Security Service hadn't asked for one, RIA Novosti said.