kovtun's would come later.two responded with a press conference in moscow stating their innocence. [ speaking russian ] >> reporter: russia refused to extradite them, so we traveled to moscow to find the men who are wanted in connection with litvinenko's murder. coming up -- the stakes get even higher as we confront a top russian official. when "dateline" continues. with this one little nexgard chew comes power, confidence, reassurance you're doing what's right to protect your dog from fleas and ticks for a full month. this one little nexgard chew is the #1 vet recommended protection. and it's the only chew fda approved to prevent infections that cause lyme disease. plus, it's safe for puppies. there's a lot of power in this one little nexgard chew. nexgard. what one little chew can do. -[ scoffs ] if you say so. ♪ -i'm sorry? -what teach here isn't telling you is that snapshot rewards safe drivers with discounts on car insurance. -what? ♪ -or maybe he didn't know. ♪ [ chuckles ] i'm done with this class. -you'