40-year-old Zelimchan Changoshivili was walking through a park in central Berlin in the middle of the day on August 23 last year when a man on a bicycle passed by and shot him to death with a silenced pistol.

German prosecutors believe that the Russian government has the highest responsibility for the murder and in a trial that begins on Wednesday, it will be decided whether the suspect is an agent who acted on the Kremlin's order.

Pistol, bicycle, wig

After the murder, witnesses saw a man throw a large bag into the river Spree, where police later found the murder weapon, a wig and a bicycle.

Shortly afterwards, a man was arrested who, according to identity documents, was a 49-year-old Russian citizen named Vadim Sokolov.

However, the documents were forged, the newspaper Der Spiegel revealed in collaboration with the UK-based journalist group Bellingcat.

The man is actually the few years older Vadim Krasikov, originally from Kazakhstan, who has been convicted of a similar murder in Moscow in 2013, according to their intelligence and comparisons of photos.

Krasikov is said to have been recruited by the Russian intelligence service FSB, which prosecutors are expected to prove with information from his mobile phone.

According to the indictment, he received an order from the authorities of the Russian central government at least five weeks before the murder.

The suspect is silent.

During the first day of the trial, he announces through his lawyer that his name is Vadim Sokolov and that he is a Russian, single engineer.

He denies any knowledge of Vadim Krasikov.

Putin: He was bloodthirsty

The murdered Zelimchan Changoshivili came from a Georgian region with a large Chechen minority and has previously fought with Chechen rebels against Russia.

Speaking in the case - after Germany expelled two Russian diplomats - Russian President Vladimir Putin described him as a "vicious and bloodthirsty assassin" and accused the Chechen of involvement in a bombing in Russia.

Russia has consistently denied the allegations and responded to Germany's expulsions of diplomats by expelling two German diplomats.