This may sound harsh, but the Russians need to interrogate as harshly as possible any of the terrorists who survived and any of their family members to find the nest of terrorists. They need to (a) try and then execute all the terrorists and (b) destroy their homes and (c) since these are Islamists, declare Islam for what it is, an organized criminal activity, and destroy all the mosques in Russia.
CNBC - 5 children dead, 310 injured - 180 of which are children