Zelimkhan Khangoshvili, a Georgian Chechen man, was shot and killed in broad daylight over two years ago on his way to a mosque in Berlin's small Kleiner Tiergarten park.
Khangoshvili had fought against Russian troops in Chechnya and despite denying involvement in his death, Russia had long classified the man as a “terrorist”.
He had previously survived multiple assassination attempts and continued to receive threats after fleeing with his family to Germany in 2016, where he had claimed asylum.
Now, a Russian man has been found guilty of the murder and sentenced to life imprisonment by a German court.
Prosecutors said that Vadim Krasikov -- who had denied the charges -- fatally shot Khangoshvili in a park on the orders of Moscow.
The Berlin regional court said in its verdict that Russian security services provided the 56-year-old with a false identity, fake passport, and the resources to carry out the killing.
The alleged political assassination has fueled tensions between Berlin and Germany, which have escalated following the poisoning of Kremlin critic Alexei Navalny.
Kremlin spokesman, Dmitry Peskov, has previously described the allegations as "absolutely groundless". But German prosecutors said there was ample evidence indicating that Russian officials were behind the order.
A lawyer for seven relatives of Khangoshvili said Russia had tried to "send a message" to other political enemies with his killing.
Who was Zelimkhan Khangoshvili?
The 40-year-old Georgian citizen had led an anti-Russian militia in the second Chechen war from 2000 to 2004, German prosecutors found.
In 2008, he was tasked with assembling a Georgian unit against the Russians in South Ossetia, but peace was negotiated before the unit was deployed.
Russian authorities had accused Khangoshvili of being a member of the "Caucasus Emirate'' extremist organisation, according to German prosecutors.
He had survived multiple assassination attempts and continued to receive threats after fleeing with his family to Germany. Then on 23 August 2019, Khangoshvili was killed in broad daylight.
What do we know about the killing?
Prosecutors say Khangoshvili's killer approached him from behind on a bicycle and shot him twice in the torso with a Glock handgun equipped with a silencer.
The victim was knocked to the ground by the force of the bullets before the assailant then fatally shot him a third time in the head.
German investigators say the killing had been "planned for a long time" and had been executed "in cold blood".
The Berlin regional court heard witnesses, who said they had alerted police after seeing a man dump a wig, clothes, and a bicycle in the nearby Spree river. The information allowed officers to arrest the suspect before he could escape the scene on an electric scooter.
The suspect was later identified as Vadim Krasikov, a Russian citizen who claims to go by the name of Vadim Sokolov.
Krasikov was found with around €3,700 and 110 Polish zlotys (>€24), which prosecutors said was to pay his expenses in Berlin and aid in his flight from Germany after the murder.
Berlin judges said on Wednesday that Krasikov bore “particularly grave responsibility," meaning he will not be entitled to automatic parole after 15 years under German custom.
How facial recognition led to the identification
Prosecutors stated that Krasikov -- using the alias Sokolov -- had travelled to the German capital in August 2019 on the orders of the Russian government. Before the shooting, they say he had also visited Paris and Warsaw as a tourist.
"The defendant took the contract, either for an unknown sum of money or because he shared the motive of those who gave the contract to liquidate the [victim] as a political enemy in revenge," Ronald Georg had told the court.
"The accused was a commander of a special unit of the Russian secret service FSB," prosecutors added in their closing statement.
During the trial, investigators revealed a private photo of Krasikov with two tattoos identical to those of the suspect.
German authorities also used facial recognition to match the suspect to a 2014 photograph distributed by Russia over a Moscow killing.
Berlin says they have found no evidence that the murder of Khangoshvili was "contracted by a non-state actor".
One month before the killing, Krasikov had obtained a new passport in the Russian city of Bryansk, which he used to apply for a French visa at the general consulate in Moscow, prosecutors said.
In his visa application, the suspect claimed to work for a St. Petersburg firm known as Zao Rust, they added.
Investigators later found that Zao Rust's fax number was one used by two firms that are operated by the Russian Defense Ministry.
Tensions heightened between Germany and Russia
The court's verdict concludes a long case that has exasperated the worsening relationship between Berlin and Moscow.
On Wednesday, the Russian embassy in Berlin denounced the court's verdict and said allegations of Russian involvement were an "absurd thesis".
"We consider this verdict to be a biased, politically motivated decision that seriously aggravates the already difficult Russian-German relations," a statement read.
"This outcome is of great concern to us, is an obvious act of hostility, and will not be left unresponsive."
Russian lawmaker Leonid Slutsky, head of the Duma's foreign affairs committee, called Germany's expulsion of diplomats "completely crooked logic".
Germany has denied claims by Russian President Vladimir Putin that he had called for Khangoshvili's extradition years previously.
After the killing, Germany expelled two Russian diplomats citing a lack of cooperation with the investigation. The move prompted Russia to oust two German diplomats in retaliation.
Two more Russian diplomats were expelled from Berlin following the court decision, Germany's foreign ministry announced.
Relations between the two countries have been further soured since allegations of Russian involvement in the 2015 hacking of the German parliament and the theft of documents from Chancellor Angela Merkel's own office.
Two weeks before Germany's recent Bundestag elections, Berlin also opened an investigation into fresh cyberattacks on MPs.
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