The investigation into the terrorist attack at a concert hall in Russia’s Moscow region on March 22 has led to the detention of four individuals in the Dagestan Autonomous Republic. The Russian Federal Security Service (FSB) revealed that one suspect confessed to financing the attack and supplying weapons to the attackers. Authorities did not disclose the nationalities of the detainees. The attack, carried out by four assailants who opened fire and set the building on fire during a “Picnic” rock band concert in Krasnogorsk, resulted in 144 fatalities.