The Swiss investigation into corruption at FIFA has widened to include the former general secretary of world football’s governing body, Urs Linsi.

The 67-year-old Swiss football administrator and businessman held the second most important job at FIFA between 1999 and 2007, the first half of former president Sepp Blatter’s controversial reign.

The Swiss authorities have been investigating a £5.6m payment made by the German FA , via FIFA, to former Adidas boss Robert Louis-Dreyfus in April 2005.

It is alleged that this was a repayment of a loan that the German FA used for bribes during the bidding process for the 2006 World Cup, which was staged in Germany.

Last November the Office of the Attorney General (OAG) of Switzerland started criminal proceedings against German football great Franz Beckenbauer and three other senior board members from the 2006 World Cup’s organising committee, including former German FA president Wolfgang Niersbach.

An OAG statement on Wednesday confirmed that Swiss police “conducted house searches” last week “at various locations in the German-speaking part of Switzerland”.

It also explained that these searches “relate to Urs Linsi”, who is described as a “further suspect”.

Germany’s successful bid for the 2006 World Cup has been dogged by allegations of wrongdoing ever since it beat South Africa’s pitch by 12 votes to 11 in July 2000.

Charlie Dempsey, a delegate from the Oceania confederation, abstained in the final round, citing “intolerable pressure”.