The 37-year-old Spanish rider, who rode alongside Lance Armstrong for three years as one of US Postal's cyclists, was taken away by French police within two hours of the positive test. He can ask for a "B" sample, although these rarely clear riders. If he does ask for it and he fails that test, too, he will be fired by the team, its directors said.
Beltran was targeted by the French anti-doping agency (AFLD) before the race had even started, after blood tests carried out July 3-4 showed "abnormal parameters," the AFLD's chief Pierre Bordry told the Associated Press.
"Yes, they were of a nature to target him, that was why he was tested" July 5, Bordry said. "The parameters were abnormal.
"There are not just traces of EPO, there is EPO," Bordry said. "Whether there is a lot or a little, EPO is forbidden."
Beltran might not be alone, either, with Bordry adding that other riders - so far unidentified - are also under the spotlight for having abnormal blood parameters.
Liquigas spokesman Paolo Barbieri said French police had taken Beltran from the team hotel to the town of Aurillac, where yesterday's seventh stage finished. He confirmed police were searching rooms.
Before the positive test, Luis-Leon Sanchez of Spain won an exciting stage and Kim Kirchen of Luxembourg retained the yellow jersey.
Kirchen still leads Australia's Cadel Evans by six seconds, with Monday's first big mountain stage approaching.
Caisse d'Epargne's Sanchez was part of a group of four riders that broke away before the major climb but was caught toward the end of the race.
The Spaniard slipped away again at the end and this time was able to hold on. Sanchez finished six seconds ahead of a large group led by former yellow jersey Stefan Schumacher of Germany and Filippo Pozzato of Italy. Kirchen was fourth.
Heads certainly turned yesterday with the news of the Tour's first doping test, which now means four ex-Armstrong teammates have tested positive in the past four years.
In addition to Beltran, Floyd Landis, Roberto Heras of Spain, and Tyler Hamilton - all former Postal riders during Armstrong's seven Tour wins from 1999-2005 - failed doping tests after quitting the Texan's team.
Though Beltran will not continue in the Tour, his team will.
Depending on what Beltran tells police, Liquigas may eventually be forced out, too.
