The German police arrested a 49-year-old Russian man, publicly identified as only Vadim S., and said he faces charges of "treacherous manslaughter." Police divers recovered the suspected weapon, a Glock 26, and a bike in a nearby river, the Berlin state prosecutor's office said on Twitter.
The midday killing had been well planned, early reports suggest. After approaching his victim from behind and shooting him at least twice, the killer biked his way a few hundred yards south to a riverbank. Two witnesses saw him throw his bike and a plastic bag into the Spree River.
The witnesses alerted the police, who found the suspect in nearby shrubs, where he had changed his clothes and appearance, and seemed ready to travel by scooter. He had a large amount of money with him, the police said.
The suspect's identity is based on the name on his Russian passport, though the document had not been verified. The man had arrived from Moscow via Paris a few days earlier, according to news reports, and was scheduled to fly back to the Russian capital.
Khangoshvili had been a target before, according to an advocate familiar with his case. He had survived at least two attempts on his life in Georgia and had sought safety in Germany.
"He was in constant danger from the Russians," said Ekkehard Maass, the director of the German-Caucasian Society, who had supported Khangoshvili's asylum application in Germany. "His death fits into a long list of targeted killings by the Russians over the past decade."
In Ukraine, the authorities have reported multiple assassinations and attempted assassinations using methods including car bombs and silenced pistols during the country's now 5-year-old conflict with Russian-backed separatists.
In 2016, an attacker on a bike in the eastern Ukrainian city of Kharkiv shot from behind and injured a former Ukrainian artillery officer, Yevgeny Sukhoveyev. In that case, the attacker pedalled away without being caught.
A year later, a man posing as a journalist for the French newspaper Le Monde tried to shoot two ethnic Chechens, Amina Okuyeva and Adam Osmayev, who were fighting on Kiev's side in the Ukraine war. The killer had claimed to be working on a story about their exploits.
Both Chechens survived, but Okuyeva was later killed when someone opened fire with a machine gun on the car she was driving outside of Kiev.
Chechen dissidents and former rebels living outside Russia have been frequent targets. In 2009, Sulim B. Yamadayev, a rival to Chechnya's leader, Ramzan A. Kadyrov, was shot and killed in a parking garage in Dubai.
In January 2017, Maass, of the German-Caucasian Society, wrote a letter to the German immigration authorities on Khangoshvili's behalf, expressing his concern for his safety.
"He is so massively pursued by the Russian side that his life is in danger and he needs special protection," Maass wrote to the authorities, specifically referring to President Vladimir V. Putin. "I urge you to grant him special protection and not to send him back to where Putin's long arm can reach him."
Written by: Katrin Bennhold and Andrew E. Kramer
© 2019 THE NEW YORK TIMES