German authorities yesterday confirmed receipt of documents from doping expert Werner Franke which show that yellow jersey winner Alberto Contador, 24, had taken drugs.

Franke had previously revealed that he had documents from last year's Operation Puerto investigation in Spain which show that Contador had taken HMG-Lepori as a testosterone booster and an asthma product called TGN.

'We can confirm we have received the documents,' said a spokesman for Germany's Federal Criminal Police Office.

Contador, who won Sunday's drug-tainted Tour riding for the Discovery Channel team, missed the 2006 Tour when his former team, Liberty, were disqualified.

This was because he and four other riders - plus the team director and doctor - were allegedly linked to Operation Puerto.

The Spanish doping investigation is one of the largest scandals in cycling history - at least 50 riders are suspected of getting sophisticated drug services, including blood doping, from a Madrid clinic.

Contador said on Saturday that his name had turned up mistakenly in the Puerto file. He has not failed any doping test.

Franke, a molecular biologist, is not the first to say he possesses copies of the Operation Puerto investigation in which Contador's name surfaces.

More than a week ago, Germany's Bild and Suddeutsche Zeitung printed documents which purport to show the customers of the Madrid clinic.

Doping scandals have devastated this year's Tour.

Iban Mayo, Alexandre Vinokourov and Cristian Moreni all failed drug tests, while overall leader Michael Rasmussen was sacked for missing dope tests and lying about his training whereabouts.

REUTERS