In 2015–16, the British Government conducted an inquiry into the death of Alexander Litvinenko. Its report states, "The FSB operation to kill Mr Litvinenko was probably approved by Mr Patrushev and also by President Putin." The report outlined some possible motives for the murder, including Litvinenko's public statements and books about the alleged involvement of the FSB in mass murder, and what was "undoubtedly a personal dimension to the antagonism" between Putin and Litvinenko, led to the murder.