Three days after the terrorist attack on a Moscow concert hall, Russian President Vladimir Putin confirmed on Monday that the mass shooting “was committed by radical Islamists,” while still continuing to hint at a potential Ukrainian involvement. The confirmed death toll from the attack rose to 139 by Monday evening, according to Deputy Prime Minister Tatyana Golikova. Four gunmen opened fire on concert-goers at the Crocus City Hall venue just outside Moscow on Friday evening just before the start of a rock concert. They also set fire to the building, collapsing the roof. Golikova said that th…