Cika wannan jumlar: A cikin 2015<unk>16, Gwamnatin Burtaniya ta gudanar da bincike kan mutuwar Alexander Litvinenko. Rahotonsa ya ce, "Tsarin FSB na kashe Mr Litvinenko mai yiwuwa Mista Patrushev ne ya amince da shi da kuma Shugaba Putin". Rahoton ya bayyana wasu dalilai masu yiwuwa na kisan, ciki har da Litvinenko na jama'a da kuma littattafai game da
zargin da ake yi na FSB a cikin kisan gilla, da kuma abin da "babu shakka wani bangare na sirri ga adawa" tsakanin Putin da Litvinenko, ya haifar da kisan kai.