The German-Caucasian Society on Friday provided The Associated Press with a letter addressed to a senior official at Germany's migration office dated Jan. 13, 2017, stating that Zelimkhan Khangoshvili's life was in danger and asking for him to receive special protection.
The group said Khangoshvili, a Georgian citizen of Chechen ethnicity who fought against Russian troops in Chechnya, survived multiple assassination attempts and continued to receive threats after fleeing to Germany.
In his letter, the group's chairman Ekkehard Maass called for the 40-year-old to receive "special protection and not to be sent to where the long arm of Putin can reach him." According to German and international news outlets a 48-year-old Russian man arrested over the killing had links to organized crime in Russia.
Weekly Focus, which first reported about the letter, claimed the suspect had tattoos commonly worn by Russian mobsters Rival weekly Der Spiegel and investigative website Bellingcat reported separately last week that the suspect's passport indicated ties to Russian intelligence.
Russia has vehemently denied involvement in the killing A spokesman for Germany's Interior Ministry, Bjoern Gruenewaelder, said the country's security services were aware of Khangoshvili, but declined to elaborate citing privacy reasons and the ongoing investigation.
The Berlin prosecutors' office said it was investigating the background to the killing but likewise declined to comment on media reports. In a rare step, Berlin police published a photograph of the suspect and called for anyone who saw the man in the days before the killing, knew where he stayed or knew him personally to come forward.