A joint investigation undertaken by an international team of journalist investigators from Bellingcat and the e-magazine The Insider has identified a key figure in the downed MH17 Malaysian airliner over Donetsk region in Russian occupied territory in July 2014. The person is General Colonel Nikolai Tkachev, chief inspector of Russia's central military sector.

"That the voice [on recordings] is identical to the voice of Tkachev has been confirmed by two independent forensic digital audio examinations. Tkachev denies he was in Ukraine," the Russian-language report of The Insider says.

Investigators say that on September 28, 2016 the Dutch-led Joint Investigation Team (JIT) appealed to witnesses to help identify those individuals suspected of involvement in the shooting down of the airliner. One individual was known by the call sign 'Dolphin' (Delfin), who was identified in recorded telephone conversations, who was also referred to as 'Nikolai Fedorovich.' The other person was known by the call sign 'Orion' and Andrey Ivanovich.

According to Bellingcat and The Insider, Nikolai Fedorovich is General Colonel Nikolai Fedorovich Tkachev.

JIT published a number of intercepted telephone calls between these Delfin and Orion, where the men address each other by their first names and patronymic.

According to Bellingcat, the National Center for Media Forensics at the University of Colorado at Denver conducted a forensic speaker comparison based on the industry-standard Likelihood Ratio (LR) analysis. In their test, they used the software package BATVOX from AGNITIO/NUANCE.

The Forensic Science Centre of Lithuania also conducted analysis on the calls individually to match them with the calls.

According to Bellingcat's report Colonel General Nikolai Fedorovich Tkachev, "Delfin," is the senior-most Russian officer who has been linked to the downing of MH17.

"Tkachev was, and still is, an active functionary in the Russian military through his ongoing role as Chief Inspector of the Central Military District. His exact role and importance for the MH17 case has not been made public so far by the JIT," the report says.

Bellingcat said before conducting forensic audio analysis, there was no direct evidence showing Tkachev’s direct link to the self-proclaimed Luhansk People's Republic (LPR) and the war in Donbas. The voice sample collected by The Insider was analyzed to firmly establish the link between Delfin and Tkachev. As shown by multiple reports, his collaboration with 'LPR' took place during the period when MH17 was downed.

Per his own words in the recent telephone conversation with the Insider, Tkachev served the Russian Armed Forces on July 17, 2014 as the Chief Inspector of Russia’s Central Military District, and continued these duties immediately after the downing and his permanent return to Russia.