German officials said on Tuesday they have received documents from German doping expert Werner Franke that he claims show Tour de France winner Alberto Contador was involved in doping.
Franke said he has documents from last year's Operation Puerto doping investigation in Spain showing that Contador, a Spaniard who won the Tour on Sunday, had taken HMG-Lepori as a testosterone booster, as well as an asthma product called TGN.
"We can confirm we have received the documents and they will be incorporated into procedures of the district attorney's office," said Christian Brockert, spokesman for Germany's Federal Criminal Police Office.
Brockert said the federal office will meet with the district attorneys and assess the documents.
Contador, who rides for the Discovery Channel team, missed last year's Tour when his former team, Liberty, was disqualified because he and four other riders -- along with 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 obtaining sophisticated drug services, including blood doping, from a Madrid clinic.
Contador said on Saturday his name mistakenly turned up in the Puerto file.
"I was in the wrong team at the wrong time and somehow my name got among the documents," Contador said, adding that cycling's governing body had corrected the mistake.
He hasn't failed a doping test.
Franke, a molecular biologist, made his reputation by researching the systematic sports doping that turned the former East Germany into an Olympic powerhouse. He has clashed with Jan Ullrich, another rider linked to Operation Puerto.
A German court imposed a gag order on Franke for disclosing how much the 1997 Tour winner paid the Madrid clinic based on documents from the investigation. It was believed there wasn't enough evidence establishing that Ullrich, who has denied doping, was a customer.
But the case is headed back to court, because Ullrich's DNA samples since have been matched to blood bags seized at the Madrid clinic.
"They weren't doing that for free," Franke said.
He isn't the first to say he possesses copies of the Operation Puerto investigation in which Contador's name has surfaced. France's Le Monde newspaper, along with several German ones, have printed parts of documents. More than a week ago, Germany's Bild and Suddeutsche Zeitung printed documents that purport to show the customers of the Madrid clinic.