Police probe Georgian's 'execution' in Berlin park

German police were investigating Sunday the assassination-style killing in a Berlin park of a Georgian former special forces commando and Chechnya war veteran.

Police have arrested a 49-year-old suspect from Russia's Chechnya republic over the shooting on Friday in the Kleiner Tiergarten park.

The victim was identified as Zelimkhan Khangoshvili by Georgia's Human Rights Education and Monitoring Center (EMC), and was aged 40, according to German prosecutors.

The killer approached Khangoshvili from behind as he was on his way to a mosque, shot him twice and fled by bicycle in what one witness described as an "execution" style killing.

"Khangoshvili died on the spot before an ambulance arrived," the EMC said in a statement.

Police divers later recovered a Glock handgun, a wig and bicycle from the nearby Spree river.

A large sum of money was found in the home of the suspect, according to Tagesspiegel daily.

The victim was reportedly a veteran of the second Chechen War from 1999 to 2009, where he served as a field commander from 2001 to 2005, and later joined a Georgian counter-terrorist unit.

In 2012, his Georgian special forces unit engaged in an operation against militants holding hostages in the remote Lopota gorge near the border with Russia's Dagestan republic.

German media said the murder was believed to be a revenge killing related to the victim's military past.

One of his sons said Khangoshvili, a father of five, had survived four previous attempts on his life.

EMC said the last attack happened in May 2015 in Tbilisi when "unknown people shot him eight times while Khangoshvili was driving, but by chance he escaped death".

"The Khangoshvili family was forced to leave Georgia and seek refuge in another country." For the past few years, they had been living in Berlin under assumed identities, German media said.

German police had, meanwhile, also listed him as a potentially militant Islamist for reasons still unclear, Bild reported.