British police have launched a murder inquiry, after a woman exposed to a Novichok nerve agent in England last week, died in hospital. Dawn Sturgess and Charlie Rowley were rushed to Salisbury Hospital last Saturday - after they came into contact with the substance. Mr Rowley remains in a critical condition. Officers are still trying to understand how the pair were exposed to the nerve agent. It's the same substance used to poison former Russian spy Sergei Skripal and his daughter in March. Reagan Des Vignes reports.