Fifa insists there is no evidence to support match-fixing has taken place at the World Cup – and the governing body has called on those accusing to the contrary to provide proof.
Convicted fraudster Wilson Raj Perumal was alleged to have correctly predicted the result of Cameroon's 4-0 defeat against Croatia before the game by German magazine Der Spiegel.
The Indomitable Lions' defeat was compounded by a first-half red card – another prediction which was reportedly made by Perumal – for Alex Song which added further fuel to the speculation foul play had taken place.
Perumal has denied that he correctly predicted the events before the game on June 18 but Der Spiegel is standing by its reports, despite the fact no evidence has been submitted to Fifa.
And Fifa's head of media Delia Fischer says allegations need to be backed up by evidence.
"We have requested Der Spiegel to provide us with all the communications with Perumal and any other material in order to prove the allegations they have made," she said.
"So far we have no evidence of any match manipulation on the betting market. The media and other stakeholders should not call people's or organisation's credibility into question just for headlines.
"It is really important to make sure that information is handled with the necessary respect and care."
Cameroon headed home after losing against Croatia, Mexico and Brazil to finish bottom of Group A and FECAFOOT's ethics committee has confirmed it will probe allegations of fraud.
But Perumal said in a statement: "Contrary to the 'revelations' published by the German weekly Der Spiegel that were picked up by news outlets worldwide, I did not predict the result of the Cameroon vs Croatia match.
"The Facebook chat with the Der Spiegel journalist took place a few days after the match – June 21st, as confirmed by my Facebook log – and was but an informal assessment of the behaviour of the Cameroon team at the Brazil 2014 World Cup after they had played two of their three group stage matches, including the one with Croatia.
"At no time did I make reference to four goals being scored or to a red card being issued."
Der Spiegel responded by saying: "We firmly stand by our assertion that Mr Perumal wrote in a Facebook chat with der Spiegel some hours before the match Croatia vs Cameroon, that the result of the match will be a 4:0 victory for Croatia and that a player of Cameroon will get a red card in the first half."
