Author: SEBASTIAN SHUKLA, CNN

Former Soviet chemist shares details of the nerve agent Novichok

"A lethal dose ... and the person will die immediately. If [the dosage] is less, [the person] will go through very tortuous scenes. They will start convulsions, and stop breathing and then lose vision, and there are other problems -- vomiting, everything. It's a terrible scene."

5 killed in church shooting in Dagestan

A shooter opened fire at a church in the Northern Caucasus region of southern Russia on Sunday, killing five people and wounding two others, authorities said, according to state media.