https://www.bellingcat.com/news/uk-and-europe/2020/12/21/if-it-hadnt-been-for-the-prompt-work-of-the-medics-fsb-officer-inadvertently-confesses-murder-plot-to-navalny/

I’m a big fan of Bellingcat’s work:

Prior to offering these rights-of-reply, Alexey Navalny requested the opportunity to confront, by telephone, members of the FSB squad implicated in his poisoning. Bellingcat agreed and arranged for its representatives to be present during the calls, for the purpose of obtaining any additional information that might be exchanged.

The calls were made beginning at 4:30 am CET (6:30 am Moscow time) from a location in Germany, where Navalny has been recuperating since his poisoning. In order to increase the chance of his calls being answered by the FSB operatives, Navalny used an IP telephony application which permits the custom-setting of a caller ID. In this case, the number that was selected for ID spoofing was that of an FSB landline which, call records showed, had been in regular communication with several of the squad members.