Police and forensics officials at a crime scene in Berlin on Aug. 23. Zelimkhan Khangoshvili of Georgia was fatally shot, and German media outlets suspect Russia was involved in the assassination-style killing. (Paul Zinken/AFP/Getty Images)

AT MIDDAY Aug. 23, a former Chechen rebel, Zelimkhan Khangoshvili, who had fought against Russian troops in the Second Chechen War, was eating lunch in a central Berlin park, the Kleiner Tiergarten. He was an ethnic Chechen, a citizen of Georgia from the Pankisi Gorge region, who had sought asylum in Germany after previous attempts on his life. Suddenly, a man emerged from some bushes on an electric bicycle, shot Mr. Khangoshvili in the head and shoulder from behind with a Glock 26 pistol, then sped off. A few minutes later, two teenagers saw the gunman discard the weapon, a wig and the bicycle in the nearby River Spree.

The teens called the police, who apprehended the killer minutes later and recovered the evidence. According to a report by the open-source investigative organization Bellingcat, along with the German publication Der Spiegel and a Russian journalism outlet, the Insider, the suspect was carrying a recently issued, valid Russian passport in the name of Vadim Sokolov. He flew from Moscow to Paris and then went to Berlin. But the investigations suggest that his identity was artificial. They reported “no such person exists in Russia’s sprawling, comprehensive national citizen database. In addition, no trace of such a person exists in a trove of hundreds of leaked residential databases” previously acquired by Bellingcat. Why is this important? Because “no person in Russia is in a position to obtain a valid Russian passport under a fake identity without the involvement of the state bureaucratic and security apparatus.”

If this sounds familiar, it should. In March 2018, Russian military intelligence officers traveled from Moscow to London to carry out the poisoning of double agent Sergei Skripal, 67, and his daughter Yulia, then 33, using a lethal Soviet-era binary nerve agent, Novichok. They also used fake identities that were later uncovered, as did a third man on the mission. The Skripals suffered illness but were not killed in the attack, although another person in Britain died after inadvertent exposure. Not to be forgotten is the 2006 assassination of Alexander Litvinenko, a former FSB officer who was killed with a bit of radioactive polonium put in his tea in a London hotel lobby by two men who traveled there from Moscow. British investigators were able to piece together these cases using surveillance footage and other evidence and did not hesitate to challenge Russia over the assassinations. Hopefully, Germany will also vigorously investigate and prosecute the case.

This is not the first time a Chechen rebel has been murdered abroad. Mr. Khangoshvili was reportedly on a Russian blacklist and may also have faced threats from other quarters. A spokesman for President Vladimir Putin has denied that Russia had anything to do with the killing. So far, the evidence is fragmentary. But if it turns out the killer came from Russia or was sponsored by the security services there, Germany must be prepared to show Moscow that it will not tolerate the abhorrent practice of sending hitmen to the Tiergarten — or anywhere on its soil.