Two Russian diplomats have been expelled by the German government following a broad daylight assassination of a Chechen exile at a Berlin park in August.

The expulsion came after Germany’s chief prosecutor decided to take over the case as confirmed in a statement released on the site of the German Foreign Ministry.

Zelimkhan Khangoshvili was murdered just a year-and-a-half after a Russian double agent Sergei Skripal and his daughter Yulia were poisoned by a nerve agent in the English town of Salisbury. The 40-year-old former Chechen rebel commander, was shot in the head from behind in the Kleiner Tiergarten park in August.

Though the suspect who entered the country using a Russian passport under the name of Vadim Sergeyevich Sokolov was arrested, he has however given little information to the police. A joint investigation carried out by Bellingcat, Der Spiegel and The Insider, revealed that the passport serial number corresponds to those issued to known Russian intelligence officers.

Germany’s foreign ministry on Wednesday December 4, said it expelled the two Russian diplomats over Moscow’s failure to help investigate the Khangoshvili murder.

“It’s clearly an event in bilateral relations that we unfortunately didn’t get any active assistance from Russia to try to solve this case,” Angela Merkel, chancellor, said on the sidelines of the Nato summit in Britain on Wednesday.

Russia’s Foreign Ministry has described the German move as “unfounded and unfriendly”, and further threatened that it will respond asymmetrically.

“Mixing politics with a police investigation is unacceptable,” a spokesman told the Kommersant newspaper shortly after the news broke. “A complex of retaliatory measures will be required in response.”