GERMANY’S DECISION to expel two Russian diplomats should not be the end of its response to the brazen killing of a former Chechen rebel in a Berlin park this past August. Germany is right to signal its unhappiness with Russia’s refusal to cooperate in the investigation. But if the probe establishes that the Russian Federation or its proxy in Chechnya dispatched the hired gun, more severe action must follow.

The victim, who used the alias Zelimkhan Khangoshvili and whom German authorities also identified as Tornike K., had fought against Russian troops in the second Chechen war and was an ethnic Chechen, a citizen of Georgia from the Pankisi Gorge region, who sought asylum in Germany after previous attempts on his life. He was eating lunch in the Kleiner Tiergarten when an assailant came out from behind some bushes in the park, on a bicycle, shot Khangoshvili in the head and shoulder from behind and then sped off. Thanks to sharp observations by two teenagers, the assailant was spotted tossing the weapon, a wig and the bicycle into a river, and he was arrested.

The suspect has refused to talk, and Russia has refused to assist. The suspect was traveling on a valid Russian passport, recently issued, in the name of Vadim Sokolov. However, this appears to have been a cover identity. The German authorities identified the man on Wednesday as Vadim K., a Russian who had been wanted by police in a 2013 murder in Moscow. Strangely, in July 2015, the Russian police search file on him was deleted, and less than two months later, a passport was issued in the name of Vadim Sokolov, whose ID photo was nearly identical to that of Vadim K. The open-source investigative journalism outlet, Bellingcat, along with the German publication Der Spiegel, the Russian journalism group the Insider, and the Dossier Center, affiliated with former Russian oligarch Mikhail Khodorkovsky, have identified him as Vadim Krasikov. The scrubbing of information about him from Russian files points to the role of the state in dispatching him as a gunman for hire, Bellingcat said.

Clearly, Germany has now grasped the seriousness of the attack and escalated the prosecution to a federal level, from a murder case to a state security threat. Peter Frank, the federal prosecutor, said new evidence was developed in recent weeks, and “there are sufficient, real indications that the killing . . . was carried out either on orders by the officials in the Russian Federation or those in the autonomous Chechen Republic, as part of the Russian Republic.” Chechnya is ruled by a Kremlin-approved strongman, Ramzan Kadyrov.

The killing recalls the 2018 attempt on the lives of Sergei Skripal and his daughter in England using a Soviet-era nerve agent, which has been traced to Russian military intelligence. No civilized nations can be indifferent to this outlaw behavior. Russia cannot be allowed to send killers with impunity to Europe or anywhere else. When the probe is complete, Germany must respond with the strongest possible measures.

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