TY JOUR TI KNOWLEDGE OF THE FEATURES OF EXTREMIST IDEOLOGY SUPPORTED BY APPROPRIATE YOUTH INFORMAL GROUPS AS A BASIS FOR INVESTIGATION OF EXTREMIST CRIMES KW extremist ideology: crimes of extremist orientation KW investigation KW criminalistic characteristic KW youth informal groups JO Vestnik of the East Siberian institute of the Ministry of internal affairs of the Russian Federation AU KUZNETSOVA, M.O. PY 2018 IS PB East Siberian institute of the Ministry of Internal Affairs of the Russian Federation