Federal prosecutors in Germany have sought life in jail without the possibility of release for a Russian man suspected of assassinating a former Chechen leader in Berlin more than two years ago on Moscow's orders.

The plea was submitted to a Berlin court on December 7 following the 14-month trial of Vadim Krasikov, a man accused of shooting dead Zelimkhan Khangoshvili, a Georgian citizen of Chechen heritage, in Kleiner Tiergarten Park in August 2019.

The suspect, apprehended just minutes after the murder, has maintained his innocence. He had entered Germany using a Russian passport with the name Vadim Sokolov on it. He was recognised by federal prosecutors as a "commander of a special unit of the Russian secret services FSB."

Prosecutor Lars Malkies summarised the evidence by telling the court that the defendant "liquidated a political opponent as an act of retribution."

Nikolaus Forschner, a co-worker, said the accused carried out a "state command to kill."

The suspect informed the court through his lawyer that he should only be known as Vadim Sokolov, who is "Russian, unmarried, and a construction engineer," at an earlier hearing. He claimed to know "no one" by the name of Krasikov. In Chechnya, Khangoshvili, 40, battled Russian forces.

After escaping to Germany in 2016, where he had been given refuge, he had already escaped three murder attempts and continued to receive threats.