The Fédération Camerounaise de Footbal will especially be looking at Cameroon's 4-0 loss to Croatia that saw midfielder Alex Song leave during the first half after receiving a red card for a particularly blatant foul.
Before the Croatia match, a man who wrote a book about match-fixing, Wilson Raj Perumal, told German magazine Der Spiegel that Cameroon would lose to Croatia by a score of 4-0 while also having a player sent off.
"Some players behaved very badly, and that's why we have conceded four goals," Cameroon coach Volker Finke told L'Equipe after the loss. "I know that it is difficult to play with ten men, but that is not a reason to lose it to this point...The behavior of some of the players is really not satisfactory. Even when we were 11-a-side, it was not acceptable."
The team also lost its other two games to Mexico and Brazil.
The Fédération Camerounaise de Football announced the investigation on its Facebook page.
"Recent allegations of fraud around Cameroon 2014 FIFA World Cup three preliminary games, especially Cameroon vs. Croatia, as well of 'the existence of seven bad apples' in our national team, do not reflect the values and principles promoted by our administration, in line with FIFA Code of Conduct and the ethics of our nation.
We wish to inform the general public that, though not yet contacted by FIFA in regards to this affair, our administration has already instructed its Ethics Committee, to further investigate these accusations. We are strongly committed to employ all means necessary to resolve this disruptive matter in the shortest delays...We wish to reinstate that in fifty-five (55) years of existence, FECAFOOT has never been sanctioned for, involved in, or even linked to match fixing or any fraud of any kind."