Seven Russian diplomats have died suddenly since November

Russian Ambassador to Turkey Andrei Karlov's body is carried in Moscow, December 23, 2016. Karlov was assassinated in Ankara, Turkey. Photo by Alexander ShcherbakTASS via Getty Images

Russia’s ambassador to Sudan, Mirgayas Shirinsky, was found dead in the swimming pool at his home in Khartoum on Wednesday, the Sudanese police said.

The ambassador, who was known to have suffered from high blood pressure, is believed to have died of natural causes, a spokesman for the police told Reuters.

WATCH: Russia announced that its ambassador to the UN Vitaly Churkin has died. Churkin, 64, fell ill while at his office Monday in New York.

Click to play video: 'Russian ambassador to UN dead after falling ill while at work'
Russian ambassador to UN dead after falling ill while at work

Russia’s foreign ministry confirmed the death Wednesday.

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Shirinsky, who was in his 60s, had been in the Russian diplomatic service since 1977, and was appointed to Sudan in 2013, had previously served in Yemen, Saudi Arabia and Rwanda.

Shirinsky is the latest in a string of Russian diplomats to die suddenly since late last year:

WATCH: The body of Andrei Karlov, the murdered Russian ambassador to Turkey arrived in Moscow Tuesday. Karlov’s wife wept as the honor guard carried her husband’s coffin off the plane.

Click to play video: 'Body of Russian ambassador to Turkey arrive in Moscow'
Body of Russian ambassador to Turkey arrive in Moscow

Other than Karlov, who was killed in front of photographers by an off-duty police officer, is there a pattern to the deaths?

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Washington Post reporter Philip Bump was skeptical in a column in March, pointing out the “human tendency to look for patterns often leads us to assume non-existent connections,” and that the life expectancy of Russian men was 65, lower than in the West. A quarter of Russian men are dead by 55.

On the other hand, a long string of people who in one way or another challenged Russian President Vladimir Putin have ended up dead, both in and out of Russia. Sometimes the killings are straightforward, sometimes elaborate.

In March, for example, Russian dissident Denis Voronenkov was shot dead in Kiev. Ex-Russian intelligence officer Alexander Litvinenko was fatally poisoned in London with a radioactive chemical in 2006. He blamed the Kremlin, but it took 10 years for British authorities to formally agree.

In 2012, Russian whistleblower Alexander Perepilichny died of a heart attack at 44 while jogging in England. Perepilichny was in good health. An expert in botanical poisons found a trace of a toxin from gelsemium, a rare Himalayan flower, in his stomach contents.

Gelsemium was also used to kill Chinese billionaire Long Liyuan, who died in 2012 after eating a bowl of cat stew laced with the poison.

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Whether any of the diplomats angered the Kremlin is not known.

With files from Reuters and the Associated Press

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