Information about the alleged detentions of senior intelligence officials first surfaced on Friday 11 March on Meduza.io, a Latvia-based news website run by dissident Russian journalists. The website quoted Irina Borogan and Andrei Soldatov, two longtime observers—and critics—of the Russian intelligence agencies. Two days later, the Sunday edition of the British newspaper The Times claimed that several senior members of the Russian intelligence agencies had been detained.

Among them, said The Times, were Sergei Beseda and Anatoly Bolyukh (or Bolukh). Both work for the Federal Security Service (FSB), which is Russia’s domestic security and counterintelligence service. Importantly, Bolyukh heads the Service for Operational Information and International Communications—known as the Fifth Service—of the FSB. As intelNews has explained, the FSB’s Fifth Service was created in 1992 to fill the vacuum left by a host of no-spy agreements, which were signed between Moscow and the governments of former Soviet Republics. These agreements prevent Russia’s Foreign Intelligence Service (SVR) to spy inside the territories of former Soviet states.

By 1995, the Fifth Service had become known as the foreign spy wing of the FSB. It grew in size drastically after 1999, and some claim it “graduated into [Russian President Vladimir] Putin’s imperial gendarme”. The Fifth Service is reportedly in charge of Kremlin’s “kill list” of Ukrainian senior officials and other dissidents who live in Ukraine. Today the Fifth Service it is led by Beseda, with Bolyukh as his deputy. Both men are said to be under house arrest, according to the reports.

The official reason given for the detentions was “accusations of embezzlement of funds”, according to The Times. However, the actual reason was “The real reason is unreliable, incomplete and partially false information about the political situation in Ukraine”, according to one source. The Times went as far as to suggest that Russian intelligence agencies were experiencing a full-scale purge of some of their most senior members. These began last week, said the paper, as teams of FSB officers conducted searches at more than 20 addresses in Moscow alone.

But other sources with contacts inside Russia dismissed the reports of an all-out purge as “exaggerated”. These sources agreed that some senior Russian intelligence officials had indeed been questioned over financial corruption, but that none of them had been placed under arrest. British newspaper The Independent said Western intelligence officials, who spoke on condition of anonymity, could not confirm that the alleged purges had taken place.