British police probing a suspected attack by Moscow on a Russian ex-spy believe he was poisoned by a nerve agent smeared on the front door of his home in southern England.
Sergei Skripal and his daughter Yulia were targeted in suspected attempted murders using a nerve agent called Novichok on March 4.
Dean Haydon, Senior National Coordinator for Counter Terrorism Policing in Britain, said in a statement: “At this point in our investigation, we believe the Skripals first came into contact with the nerve agent from their front door.
“We are therefore focusing much of our efforts in and around their address,” in the medieval cathedral city of Salisbury.
Poland expelling four Russian diplomats
Poland announced earlier this week that it was expelling four Russian diplomats as part of a coordinated international response to the attack in Britain.
“The aim is to show solidarity with Great Britain,” Polish Foreign Minister Jacek Czaputowicz told a press conference on Monday.
Czaputowicz said earlier this month Warsaw was “certain” that Moscow was involved in the suspected nerve agent attack.
Moscow has denied allegations of Russian involvement.
Britain’s Metropolitan Police said in a statement on Wednesday that traces of a nerve agent had been found at some of the other scenes detectives have been working at over the past few weeks, but at lower concentrations to that found at Skripal’s home address.
“This is one of the largest and most complex investigations undertaken by British counter terrorism policing,” the statement added.
Around 250 counter-terrorism detectives are working around the clock on the investigation, “supported by a full range of experts and partners,” the Metropolitan Police added.
Officers are trawling through more than 5,000 hours of CCTV footage and examining “over 1,350 exhibits that have been seized,” police said. Around 500 witnesses have been identified and hundreds of statements taken.
Former Russian intelligence officer Skripal was sentenced to 13 years in prison on charges of spying for Britain. In 2010 he was exchanged in a spy swap.
He and his daughter are reported to be in a critical condition in hospital.