the pair were found unconscious in a public area in southern england and a police officer who arrived on the scene is also hospitalized. let's go live to cnn senior correspondent nick peyton walsh. he is over in london at scotland yard. what are you learning? >> reporter: wolf, a staggering change, frankly, in an event that occurred about 4:00 a lazy sunday afternoon in a shopping center in a rural town of salsbury. sergei skripal who worked mi 6 and swapped and found himself in rural england, visited by his daughter yulia from russia. very close to the birthday of his son who died recently, i know what his wife. a sad family tale. we've gone from that moment a bench to a remarkable revelation to british police. this is with a they said hours earlier. >> reporter: having establish that had a nerve agent is the cause of the symptoms, leaving to us believe this is attempted