Swiss authorities conducted a new raid on FIFA on Thursday to seize evidence in the ongoing investigations of Sepp Blatter and Jerome Valcke.
The Office of the Attorney General of Switzerland (OAG) confirmed on Friday that it conducted the search and seized documents and electronic data as part of its probe that initially began into the circumstances surrounding the bidding for the 2018 and 2022 World Cups.
A statement from the OAG read: "As part of the ongoing criminal investigations in the FIFA affair, the Office of the Attorney General of Switzerland (OAG) carried out a search of FIFA's headquarters on June 2, 2016 with the aim of confirming existing findings and obtaining further information.
"Documents and electronic data were seized and will now be examined to determine their relevance to the ongoing proceedings.
"The investigations still relate only to the persons named in earlier statements issued by the OAG and further persons unknown. As proceedings are ongoing, no further information can be given at present."
Swiss attorney general Michael Lauber opened criminal proceedings against former FIFA president Blatter last September, and in March against former FIFA secretary general Valcke.
Both are suspected of criminal mismanagement of FIFA money. Blatter and Valcke deny wrongdoing but were banned for six and 12 years, respectively, by FIFA's ethics committee.
An OAG spokeswoman confirmed to Reuters that the investigation does not relate to FIFA president Gianni Infantino.
FIFA had said on Thursday that formal proceedings were yet to be taken against Infantino despite reports in German newspaper Die Welt that he is facing a 90-day suspension.
A spokesman for the organisation had told Sky Sports News: "We are not in a position to indicate if we have or have not [begun] preliminary investigatory proceedings against an individual.
"We would however like to point out that there are no formal proceedings going on against Mr Infantino."
Infantino was elected FIFA president in February following Blatter's suspension from all football activity.
Information from the Press Association and Associated Press was used in this report.