Fifa has denied being slow to react to fears that two international friendly matches were being targeted by match fixers.
The games between Bolivia and Latvia and Estonia and Bulgaria are now the subject of an investigation by the world governing body, who have opened disciplinary proceedings against six match officials.
Officials from the Estonian FA had alerted Fifa and Uefa to their concerns over the organisation of the games two weeks before the fixtures were played in Turkey on 9 February. The games went ahead and a reported €5m (£4.3m) was gambled on the Estonian match, a 2-2 draw. Industry insiders have suggested the "over two-and-a-half goal market" as the key area in a gamble originating in the Far East.
According to Latvian sources there was only around €100,000 (£86, 500) bet on their game, although that is still a large figure for such a low-profile fixture.
Fifa, who recruited a new head of security with extensive international policing experience prior to last year's World Cup, say they received "un-specific suspicions passed on through Uefa. An investigation was commenced through Fifa Security and Early Warning System was alerted.
"This investigation involved pre-match and during-the-match inquiries, and is actively continuing in several jurisdictions. We are cooperating with relevant agencies on these matches and other emerging aspects, in addition to our disciplinary proceedings. The involved national federations have been informed and information requested from them to support the internal disciplinary and the external investigative actions.
"Fifa considers this issue as a very serious one, and we are working on several fronts to tackle the matter."
One of the main tasks for Fifa has been trying to establish without doubt which official took which role for each game. Fifa have not named the officials who are facing proceedings, but three Hungarians have been suspended by their federation. The Bosnian FA has issued life bans to three of their officials, named as Sinisa Zrnic, Kenan Bajramovic and Riza Ridzozovic.
According to the match result sheet issued six days after the game by Footy Media International, the Thai-based company that set up the matches, and seen by The Independent, the referee for Latvia v Bolivia was Bajramovic Kenan and the assistants Kunic Ratko and Zrnic Sinisa, although other sources have claimed that Zrnic was in fact the referee.
None of the officials named for either match appear on Fifa's list of referees. The Bolivian FA remain unsure as to the identity of the referee for their game, a 2-1 victory for Latvia in which all three goals were penalties. A statement by the Bolivian FA said: "We asked [Fifa] to check if the referees from the Czech Republic were the ones who took charge of the match and if they had Fifa credentials."
One of the Estonian party has said that he was told the officials were from Bosnia but when he spoke to them they claimed to be from Croatia. Others involved have spoken of the peculiar circumstances surrounding the entire event. A senior member of one delegation said the organisers were represented by a man called Anthony – they were never told his surname.
According to reports in Singapore, Anthony Santia Raj represented Footy Media International. Neither he nor the company have since been traced.