German federal prosecutors believe Russian intelligence was involved in the August killing of a Georgian citizen in Berlin and want to take over the investigation, a legal source told Reuters on Tuesday, confirming a report by public broadcaster ARD.
The measure could raise tensions between Germany — and other western countries — and Russia, after strains over the poisoning of a former Russian spy, Sergei Skripal, and his daughter on British soil last year.
Zelimkhan Khangoshvili, 40, who had previously fought alongside anti-Moscow separatists in the Russian region of Chechnya, was shot twice in the head in a central Berlin park in August as he was heading to a mosque.
"We have evidence that a foreign intelligence agency was behind it and therefore the case is going to be taken over by the federal prosecutor this week," said the source, who declined to be named.
A suspect was detained shortly after the killing and Der Spiegel weekly has reported that his passport number links him to Russian security services.
Berlin prosecutors, who have so far led the case, said the suspect had been caught as he tried to dispose of the presumptive murder weapon in the nearby Spree River, along with a bicycle he had been riding.
Russia fought major campaigns in 1994-96 and 1999-2000 against separatists in Chechnya, situated in the Caucasus Mountains on Russia's border with Georgia. Many anti-Moscow fighters from those wars now live in exile and are at odds with the pro-Russian authorities in Chechnya.