Another high-ranking Russian diplomat has been killed, according to Russian authorities.
Petr Polshikov, 56, was found dead in his home in Moscow, with a bullet wound to his head, London's Evening Standard reported.
Russian authorities disclosed the murder on Dec. 20, a day after Andrei Karlov, the Russian ambassador to Turkey, was shot dead by a Turkish policeman in front of a crowd at an art gallery on Dec. 19.
The policeman, 22-year-old Mevlut Mert Altintas, fired a single round into Karlov's back and shouted "Do not forget Aleppo! Don't forget Syria!" as the Russian ambassador collapsed and died on the floor of the gallery.
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Altintas was later killed in the response to the attack, according to CNN, which said the gallery was in a "posh neighborhood" that includes hotels in addition to foreign embassies and Turkish government buildings.
In the Polshikov shooting, police said the diplomat's wife was home at the time her husband was killed, but she wasn't harmed. Investigators found a gun under the sink in the bathroom, the Evening Standard reported, while they also found a pair of bullet shells in the home.
Unlike the Tarkov shooting, Polshikov's death is shrouded in mystery -- authorities said they're looking at all leads, but hadn't publicly identified a suspect or hinted at any motivation Polshikov's killer may have had.