A Swiss corruption probe into the awarding of the 2006 World Cup to Germany was broadened on Wednesday to include former FIFA general secretary Urs Linsi after police raided homes.
But on Wednesday the top Swiss prosecution authority said it was now also investigating Linsi, who served as FIFA's secretary general from June 1999 through June 2007.
In a statement sent to AFP, OAG said that on November 23 "it conducted house searches with the support of the Federal Office of Police (fedpol) at various locations in the German-speaking part of Switzerland."
It said that all the searches related to Linsi.
When contacted by AFP, FIFA refused to comment on an ongoing investigation.
The case first came to light in October 2015, when German news magazine Der Spiegel accused Germany of using a secret slush fund holding 10 million Swiss francs (6.7 million euros according to the exchange rate at the time), to buy votes in support of its bid to host the 2006 World Cup.
The money was allegedly provided in 2000 by the late Robert Louis-Dreyfus, who at the time was head of German sportswear giant Adidas, at the request of Beckenbauer, who headed the committee promoting Germany's candidacy to host the event.
As a German company and a partner of the German football federation, Adidas had a financial interest in the World Cup being hosted in the country.
The OAG alluded to the allegations, saying Wednesday that last week's house searches were linked to "a payment of 6.7 million euros made in April 2005 by the German Football Association (DFB) to Robert Louis-Dreyfus."
It did not explain further.
According to Der Spiegel, DFB had borrowed the cash from Louis-Dreyfus in order to buy the votes of four Asian members of FIFA's 24-strong executive committee, meaning the 2005 payment could conceivably be a reimbursement.
The so-called Freshfields report, based on an inquiry into the allegations commissioned by the DFB, confirmed last March that the football federation had borrowed the 10 million Swiss francs from Louis-Dreyfus, but was unable to conclusively say how the funds were used.
German authorities have also been investigating the allegations, and in November 2015 they searched the DFB headquarters and the homes of a number of its top executives.
Linsi, who was second-in-command at FIFA at the time of the alleged payments, temporarily suspended his duties last week as head of the small Zurich Bank Sparhafen.
According to financial newsletter Inside Paradeplatz, he told the bank he wanted to clarify the allegations against him and denied any wrongdoing.
FIFA is struggling to exit a vast corruption scandal.
In addition to the suspicions surrounding the awarding of the 2006 World Cup, investigations have been opened into corruption allegations linked to the awarding of the upcoming 2018 World Cup in Russia and the 2022 tournament in Qatar.
The biggest scandal erupted in May 2015, with the high-profile arrests of FIFA officials at a luxury Zurich hotel, following a request from US prosecutors.
Dozens of football and sports marketing executives have since been indicted over allegedly receiving tens of millions of dollars in bribes and kickbacks.
Disgraced former FIFA president Sepp Blatter and his former right-hand man Jerome Valcke were the most prominent casualties at FIFA during more than a year of unprecedented scandal at the organisation.
Both men have been slapped with multi-year bans from football over ethics violations and are facing investigations by Swiss prosecutors.
Gianni Infantino replaced Blatter as world football's most powerful figure last February and vowed to crack down on the graft that had tainted FIFA's name.