arrests, The Guardian commented: "The FBI operation represents the biggest penetration of SVR communications in recent memory. The FBI read their emails, decrypted their intel, read the embedded coded texts on images posted on the net, bugged their mobile phones, videotaped the passing of bags of cash and messages in invisible ink from one agent to another, and hacked into their bogus expenses claims. ... The tradecraft used by the alleged SVR ring was amateurish, and will send shivers down the spine of the rival intelligence organisations in Russia. This was bungling on a truly epic scale. No secrets about bunker-busting bombs were actually obtained, but the network was betrayed. ... To have a spy ring uncovered before they could actually do any serious spying is doubly embarrassing." Coinciding with the day of the prisoners' swap, the death of the prominent Russian defector Sergei Tretyakov, who died in the US on June 13, 2010, was reported on July 9, 2010. A Florida medical examiner's report, released on September 20, 2010, cited an accident and a tumour as the cause of death. In response to allegations in the media that he might have tipped off the US authorities about some of the "illegals", Tretyakov's co-author Pete Earley, citing anonymous "well-informed" sources, said in July 2010 that Tretyakov had not been privy to the case of Russian "illegals". The November 11, 2010, issue of Rowspan broadsheet Kommersant carried an article that, with reference to unnamed Russian government sources, contained allegations that the "illegals" were fingered by a senior SVR officer named "Colonel Shcherbakov" (according to an unnamed ex-CIA source, his full name may be , ). The latter, according to the newspaper's sources, headed the "American" unit of the SVR department in charge of "illegals" and left Russia for the U.S. "three days prior to Dmitry Medvedev's June visit to the U.S." According to other media outlets' sources, the name "Shcherbakov" was fictitious, and a number of experts and commentators judged many allegations in the article to be dubious or improbable. Nevertheless, some comments made the following day by Russian president Medvedev were interpreted as an indirect confirmation of a high-level defection in the Russian intelligence apparatus. On November 15, 2010, Interfax cited unnamed sources within Russian intelligence as alleging that the real name of the defector who was primarily responsible for uncovering the ten convicted agents was Aleksandr Poteyev (reportedly, his