Oleg Vladimirovich Ivannikov, an officer of the Russian military intelligence agency's (GRU) Main Directorate of the General Staff, took a lot of precautions to cover up his identity. But he couldn't hide his "atypical" voice.

The 51-year-old has been fingered in a joint investigation by open-source researchers at Bellingcat, The Insider, and the McClatchy Washington bureau, "with very high certainty" as being a missile specialist who was in charge of military operations in eastern Ukraine during an "undercover deployment" by Russia at the time of the downing of Malaysia Airlines Flight 17 in 2014.

It says Ivannikov is sought by the Dutch-based international Joint Investigating Team (JIT) tasked with identifying suspects in the missile attack.

Bellingcat also identifies Ivannikov as a "reclusive" senior defense official in a breakaway region of Georgia that enjoyed Russian military support during a lightning war for independence a decade ago.

The investigation connected several of the dots based on documentation to lead them to the man with the call sign "Orion." But it was several phone conversations that helped fill out the picture, including a crucial one on July 13, 2015, that Bellingcat said was "most likely" directly related to the downing of MH17. The route and convoy described in the call matched that of the Russian Buk missile launcher thought to have been used to bring down the passenger aircraft in the skies over Ukraine.

"The Bellingcat-led investigating team used primarily open-source data sources to reconstruct a curriculum vitae of Oleg Ivannikov," the research group said in a May 25 report that identifies Ivannikov, who is also known under the alias Andrey Ivanovich Laptev, according to Novaya Gazeta.

"The military adviser who went by the name Andrey Ivanych...possesses two traits that matches the 'Andrey Ivanovich' from the intercepted calls: a distinctly high voice, and a background in military intelligence," it added. Ivanych is a colloquial variant of the patronymic "Ivanovich."

Bellingcat said it first attempted to identify the persona behind Orion by identifying all possible candidates with matching names.

But since Andrey Ivanovich is a relatively common name-patronymic combination among Russian names and the unlikelihood he would use his real name in communication on open phone lines, investigators needed a different starting point for the identification process.

Using phone intercepts, they traced the number of the call, which eventually was traced back to a user named Orion with an anonymous prepaid SIM card.

"This discovery provided Bellingcat with an initial confirmation that the persona behind 'Orion' is indeed known as 'Andrey Ivanovich' and plausibly linked to GRU," the report said.

After further investigation that tied Ivannikov to the phone number, researchers eventually were able to begin attempts at getting a voice sample to back up suspicions that this was their man.

Eventually, they reached Ivannikov on the pretext they were trying to contact another man with the same name who was well-known as the head of a Russian NGO.

During the conversation, Bellingcat said, Ivannikov implicitly confirmed his name by joking that while he shares the name of the NGO head, he could only wish to be as famous.

"Despite the fact that both audio fragments are too short for forensic computer-assisted audio analysis, a linguistic and acoustic comparison of the two voices compellingly points to the voices belonging to the same person, as both samples' high-pitched timbre and vocal intonation are highly idiosyncratic and rare among male voices," the report said.

With reporting by CurrentTime TV, a Russian-language network run by RFE/RL in cooperation with VOA