The Russian connection to a Berlin hit job that Germany doesn't want to talk about

Forensic teams examine the site where Chechen exile Zelimkhan Khangoshvili was killed.

Berlin, Germany (CNN)Murders happen in Berlin. They're not common -- the crime rate in Germany is currently at its lowest level in more than 25 years -- but as with all major cities, the occasional violent killing is all but inevitable.

What's far less common is for them to occur at noon, in the city center. And what's truly unprecedented is when the target is a former Chechen fighter, and the suspect an alleged Russian government hitman.
But that's exactly what happened on August 23.
    Zelimkhan Khangoshvili, a 40-year-old Georgian citizen of Chechen descent, was on his way to midday prayers at a mosque in the Moabit district of downtown Berlin.
    A man following him on an electric bicycle approached and shot him at close range twice in the head and once in the shoulder. Khangoshvili died instantly; his suspected killer was apprehended and remains in police custody.
    If the alleged assassin was trying to be discreet, it's fair to say he failed. Two teenagers saw him throwing a handgun, wig and bike into the River Spree, setting off a murder mystery that has gripped the country and raised uncomfortable questions about Germany's complex relationship with Russia.
    The suspect, who was carrying a Russian passport, was arrested within hours. But more than two months later, the case is still in limbo: the suspect won't talk, the Kremlin denies involvement, and Germany refuses to point the finger at Moscow without definitive evidence.
    The murder has also cast a dark shadow over the tens of thousands of other Chechen migrants living in Europe. Vulnerable to deportation, and rising anti-migrant sentiment, they say they're closely watching Germany's response to the incident.

    'We were in shock'

    Khangoshvili had long been a wanted man. His participation in the Second Chechen War, where he fought alongside fellow Chechen insurgents against Russian federal forces, earned him deep enmity among sections of Russia's armed forces.
    Despite leaving the resistance movement in around 2005, he could not shake off his past so lightly.
    Numerous assassination attempts dogged him and his young family over the years as they sought refuge across Europe, finally coming to Germany in 2016 in the hope of finding a safe haven at last.
    They could not have been more wrong.
    Zelimkhan Khangoshvili
    Khangoshvili applied for asylum three times but was rejected at each, according to Mansur Sadulaev, head of the Chechen-focused human rights advocacy group Vayfond in Sweden. Both Germany's immigration authority and the prosecutor in the case declined to confirm the number of applications Khangoshvili submitted.
    "All his requests were ignored," he said, despite the previous assassination threats and his respectable family status. Khangoshvili's wife at the time, Manana Tsatieva, was previously a doctor at a leading private hospital in the Georgian capital, Tbilisi.
    The final successful attempt on Khangoshvili's life, when it came, was still unexpected for Europe's Chechen community.
    "We were in shock," said Sadulaev. "This had only happened once before, with [Umar] Israilov," he said, referring to the former Chechen rebel who was killed in Vienna in 2009. Austrian investigators believe the Chechen government was involved in the killing.
    "No one expected that would be repeated," said Sadulaev. "The first time could have been a mistake, but the second time was a message. A very clear one."

    A wanted man

    Khangoshvili, who came from Georgia's Pankisi Valley -- a remote mountainous region on the border with Chechnya, in the North Caucasus -- grew up surrounded by war.
    The valley was a place of refuge for thousands of civilians fleeing the Second Chechen War, which raged almost a decade, beginning in 1999. Among them were Chechens who had fought against the Russian troops.
    Khangoshvili, an ethnic Chechen Georgian national, first began fighting against the Russian forces in 2001, his ex-wife Tsatiev told CNN.
    "To join the forces who were fighting for an independent country -- it was completely normal," said Tsatieva, a small woman, elegantly dressed in a flowing skirt and headscarf, who moved to Germany with Khangoshvili and their four children.
    ''At that time, it was the best thing you can do for your country."
    A police diver searches for evidence in the River Spree, close to where Khangoshvili was murdered.
    In the late 2000s, Khangoshvili settled in the Georgian capital, Tbilisi. It was then that the assassination attempts began.
    The first of these was in 2009, according to Aleksandre Kvakhadze, a research fellow at the Georgian Foundation for Strategic and International Studies, who first met Khangoshvili around this time; it was the start of a long friendship.
    "A group tried to poison him, but it didn't work," Kvakhadze said, adding that Georgian security services found the group was linked to Russian intelligence and Chechen leader Ramzan Kadyrov.
    Kadyrov is a former warlord known for his brutality -- and for his allegiance to Russian President Vladimir Putin.
    In the group's eyes, it would have been bad enough that Khangoshvili had fought in Chechnya.
    But he earned further Russian enmity by organizing a group of volunteers -- "about 200" of them, according to Kvakhadze -- from his native Pankisi Valley to fight invading Russian forces during the 2008 Russia-Georgia War.
    The volunteers did not have the chance to deploy alongside Georgian regulars, according to Kvakhadze. But they nonetheless planned to aid in the defense of the capital, if it came to that.
    Khangoshvili's contacts with former comrades came in handy in August 2012, when a group of roughly 20 Chechen and Dagestani militants were cornered by Georgian security forces on the border with Russia.
    Officials with then-president Mikheil Saakashvili's government brought in Khan