Keller was ruled to be outside of his "competence" when questioning an individual close to Infantino over the President's use of a private jet from Suriname to Switzerland.

The court ruled that the transcript of questioning of the individual be removed from the files.

"The court takes the position that the questioning was an actual interrogation for which the extraordinary public prosecutor of the Confederation was not competent in November 2020," said a press release from Keller's office.

FIFA welcomed the decision, condemning Keller and the investigation.

"Stefan Keller acted illegally by extending his investigation beyond its remit," said a FIFA statement.

"Mr Keller was appointed to look into certain meetings that the former Swiss Attorney General, Michael Lauber, had with the FIFA President Gianni Infantino.

"However, instead of doing this, Mr Keller, who has yet to even interview the FIFA President after nine months, started looking into things that have nothing to do with his appointed mandate."

In response to Keller's statement that claimed there were "clear indications of criminal conduct on the part of the FIFA President", FIFA said that this was an "unfounded and defamatory statement" and called the investigation "illegal, null and void."

These four complaints were made by Infantino's team in December 2020, with the other three still to be ruled on.

Despite this defeat for Keller, he made it clear in a statement that the criminal investigation would continue.

Keller is continuing to act as the attorney general extraordinary for the "unrecorded conversations" case involving former federal prosecutor Michael Lauber and Infantino.

The investigatory chamber of FIFA's Ethics Commission both opened and closed an investigation into Infantino’s conduct in August.

Criminal proceedings were opened in July against Infantino in Switzerland over dealings between the FIFA President and Lauber.

The case centres on undocumented meetings that Lauber and Infantino are alleged to have held in 2016 and 2017.

Infantino has insisted his innocence, saying the meetings "were in no way secret and most certainly not illegal".

Infantino became a member of the International Olympic Committee in January.

He became the FIFA President in 2016 and was re-elected in 2019.