TOPSHOT - Pedestrians walk past barriers across Rollestone Street, outside the John Baker House Sanctuary Supported Living in Salisbury, southern England, on July 7, 2018. The exposure of an apparently random British couple to the same nerve agent used against former Russian double agent Sergei Skripal, in the same part of southwest England, has sent officials scrambling to discover the source of the contamination. / AFP PHOTO / NIKLAS HALLE'N