It is Russian president Vladimir Putin who's responsible for the poisoning of Sergei and Yulia Skripals, the first being the former agent of Russian military intelligence. James Mattis, the U.S. Secretary of Defense said this as quoted by The Hill.
'Certainly, he's responsible as the head of state', the official claimed.
'They’re doing things that they believe are deniable. They take the insignia off soldiers’ uniforms and they go into Crimea. ... They point out that they can’t be proven that they tried to kill the person in Salisbury. ... They’re trying to break the unity of the Western alliance, NATO,' he carried on.
Mattis underlined that the chemical agent was deployed 'for the first time in Europe since World War II'.