A report into the 2006 World Cup corruption allegations has concluded a payment of 6.7million euros ($7.37m) from the German football federation (DFB) to world governing body FIFA in April 2005 cannot be ruled out.
Freshfields Bruckhaus Deringer, the international law firm brought in by German authorities to investigate, on Friday published a 380-page report detailing the movement of funds from account to account.
However, a lack of evidence - some of which appeared to have been mislaid or destroyed - meant the investigation was ultimately inconclusive.
"We cannot prove that votes were bought, but we cannot rule this out either," the report said.
The Freshfields report did discover, however, that the sum ended up in an account in Qatar, although no reason could be found for why it finished in an account owned by the former FIFA executive committee member Mohamed bin Hammam. The Qatari was banned for life from all football-related activity in 2011 after being found guilty of bribery in relation to that year's FIFA presidential election.
Former DFB president Wolfgang Niersbach resigned late last year as the allegations were made public.
The report revealed how Niersbach had been aware of the flow of the money before it became public knowledge.
FIFA released a statement in which it promised to "review the report carefully and factor the findings into its ongoing internal investigation of this matter", welcoming the Freshfields report's findings.
Freshfield's Christian Duve addresses a press conference with board members of the German Football Federation.
"FIFA shared information with the DFB to assist with its investigation and, in turn, received information from the DFB that is helpful to FIFA's own investigation," continued FIFA's statement.
"However, many questions still remain to be answered. FIFA's investigation has been hampered by the fact that key witnesses were not willing to answer questions or provide documents.
"FIFA maintains its victim status in all investigations and continues to co-operate with the Swiss and German authorities, who are in the best position to obtain all of the information necessary to understanding the facts of this matter."
According to the Freshfields report, former FIFA president Sepp Blatter had refused to give evidence, with his solicitor using his FIFA suspension as a motive to decline.
Former FIFA executive committee members were among a "group of people who we would have liked to have spoken to, but who were unavailable for comment," the report said.
Robert Louis-Dreyfus, the former chief executive of sportswear manufacturer adidas, and Robert Schwan, whose accounts were involved in the flow of money, have since passed away, as has the former DFB president Gerhard Mayer-Vorfelder.
"As a result of these restrictions, we cannot today provide a conclusive picture," the report said.
Board members of the German Football Federation (L-R) treasurer Reinhard Grindel, co-vice president Reinhard Rauball, co-vice president Rainer Koch and DFB media director Ralf Koettker.
Franz Beckenbauer, who led the DFB's bid for the 2006 World Cup and was subsequently president of the organising committee, was also involved in the flow of money.
An account he shared with Robert Schwan was the source of four payments to a Swiss law firm, with the reference "Obtaining TV and marketing rights for Asia, 2006 games" given for the bank transfer.
According to the report, it was Schwan who initiated these payments between May 29 and July 8, 2002, and there was "no plausible reason" for such transfers to be made.
That money later found its way to Qatar, onto the account of scaffolding company Kemco, which was owned by Bin Hammam. After Beckenbauer made a trip to Qatar in 1999, and met with Bin Hammam as part of a DFB delegation, Bin Hammam said: "Yes, Beckenbauer asked for my backing and Qatar vote to host the tournament.
"The matter is under study... we are with the best bidder... Beckenbauer also proposed co-operation between Germany and Qatar in the sports field and exchange of expertise."
Franz Beckenbauer was involved in the flow of money which saw 6.7million euros end up in the account of former FIFA executive committee member Mohamed bin Hammam.
Upon returning to Germany, Beckenbauer said at a DFB board meeting that the trip had been a success.
Beckenbauer has admitted that the 6.7million euros payment was a "mistake" but has strenuously denied that the money was used to buy votes.
''I, as the president of the organisation committee at the time, carry the responsibility for this mistake,'' Beckenbauer told the German newspaper Bild in October.
''In order to obtain financial support from FIFA, a suggestion by FIFA's finance commission was followed which, in hindsight, should have been rejected.
''No votes were bought in order to win the right to stage the 2006 World Cup.''
