Grigori Rasputin was killed at the Yusupov Palace in Petrograd on the night of 29–30 December 1916. Felix Yusupov, Grand Duke Dmitri Pavlovich, and Vladimir Purishkevich all confessed involvement. The standard account holds that Rasputin was poisoned, shot multiple times, and drowned in the Neva River. Andrew Cook's 2005 BBC-commissioned research introduced the claim that SIS officer Oswald Rayner was present and fired the final — coup de grâce — shot to the forehead, acting on British intelligence concerns that Rasputin would push Russia toward a separate peace with Germany. Some forensic and archival evidence supports British presence; the specific "Rayner fired the kill shot" claim remains unproven but is not implausible.