Sepp Blatter, the former world football chief, arrived on Monday for final hearings with a Swiss prosecutor in a fraud probe surrounding a 2011 FIFA payment to Michel Platini.
Former FIFA president Blatter, 85, is being investigated over a two million Swiss franc ($2.2 million, 1.85 million euro) payment to Platini, who was then in charge of European football's governing body UEFA.
The final hearing in the investigation was postponed to August due to the retired Swiss football administrator's poor health.
In March, he was convalescing in a clinic after spending two months in hospital in December and January.
Due to Blatter's condition, the hearing with a federal prosecutor from the Office of the Attorney General (OAG) of Switzerland can only last for around 90 minutes.
The hearing could therefore continue on subsequent days this week, if required.
Joseph "Sepp" Blatter became FIFA's general secretary in 1981 and the president of world football's governing body in 1998.
Blatter and Platini, 66, found themselves at the centre of a Swiss investigation.
"Specifically, the criminal proceedings against Joseph Blatter are now being conducted on suspicion of fraud, breach of trust and unfaithful business management," the OAG said in a statement ahead of the hearing.
Under the Code of Criminal Procedure, in lengthy and complex proceedings, "the accused are questioned one last time before the investigation is concluded, and asked to comment on the results of the investigation", the OAG added.
The OAG said the presumption of innocence applied to all parties in the proceedings and it could not put a time frame on concluding the investigation.