British police have determined a former Russian double agent and his daughter who were the victims of a nerve agent attack first came into contact with the poison at their front door.
The Metropolitan Police’s Counterterrorism Command in London, which is leading the investigation into the March 4 attack on Sergei and Yulia Skripal, said Wednesday the highest concentration of the nerve agent was found at their home.
The authorities called the investigation into the attack one of the “largest and most complex undertaken by British counterterrorism policing.”
Sergei and Yulia Skripal were found unconscious on a park bench in Salisbury, England. It was determined they were attacked with a military-grade nerve agent of the type developed by Russia.
British Prime Minister Theresa May said this month the British government concluded Russia was behind the attack, and leaders of the U.S., France, and Germany agreed Russia was to blame.
British police said 250 counterterrorism detectives are working on the investigation into the poisoning. Officers are combing through more than 5,000 hours of surveillance footage and examining 1,350 exhibits that were seized. Law enforcement has also identified roughly 500 witnesses.
Though the highest concentration of the nerve agent was found on the front door of the Skripals’ home, traces were also found at other scenes where British detectives have been working, though at lower concentrations.
Russia has denied involvement in the poisoning.
But in response to the attack, President Trump ordered the expulsion of 60 Russian diplomats from the U.S., as well as the closure of the Russian consulate in Seattle.
Countries worldwide joined the U.S. in retaliating against Russia for its nerve agent attack, including 14 member nations of the European Union.
