The lead rider of a Tour de France team caught up in a doping investigation said he had "nothing to hide" after two unnamed members of the French outfit were briefly detained before being released.

Colombian rider Nairo Quintana, 30, leader of the Arkea-Samsic team and winner of the 2014 Giro d'Italia, said no drugs were discovered during the investigation.

"No doping substance has ever been found," Quintana said in a statement late on Tuesday.

"I have nothing to hide and have never had anything to hide."

Police detained two people from the Arkea-Samsic team on Monday, with press reports saying they were a doctor and physiotherapist.

Marseille prosecutor Dominique Laurens confirmed Wednesday that the pair, whom he had said had "many health products including drugs in their personal belongings, but also and above all a method that can be qualified as doping", had both been released Tuesday.

"The investigation is ongoing," Laurens said, adding that new developments were possible.

"Investigations and hearings (must) be carried out before the public prosecutor reaches a decision on the basis of the elements collected."

A source familiar with the matter told AFP that searches had targeted several riders including Quintana's brother Dayer, as well as members of the medical team.

Nairo Quintana finished the Tour in 17th place, more than an hour behind Pogacar. Quintana's teammate Warren Barguil finished in 14th place.

It is the most significant investigation in years for the repeatedly scandal-hit Tour, which wrapped up Sunday in Paris with a surprise victory for 21-year-old debutant Tadej Pogacar, the youngest winner in more than a century.

The Tour was rocked by a major probe in 1998, when customs officials stopped a vehicle laden with doping products and the Festina team was thrown off the race as the peloton headed into Paris.

Most notoriously, Lance Armstrong, who won from 1999-2005, admitted doping in 2013 and the American was stripped of his record seven titles.

Huge disappointment

The French team's general manager Emmanuel Hubert told AFP the probe involved only "a very limited number of riders, as well as their close entourage who are not employed by the team".

"But if it turned out that at the end of the current investigation, elements came to confirm the truth of doping practices, the team would immediately dissociate itself from such acts and would take the necessary measures without delay," Hubert said.

He added that the investigation "does not target the team or its staff directly".

The probe will have come as a huge disappointment to organisers after positive headlines about the against-the-odds organisation of the race and the drama that saw Pogacar seize victory late in the race.

Many had predicted the Covid-19 pandemic would prevent the riders making it the 3,400 kilometres (2,100 miles) from the Mediterranean city of Nice to the French capital.

The prosecutor's statement said the investigation was focused on the prescription of a substance or banned method for athletes, as well as help and encouragement in its use.

The charges can lead to up to five years in prison and a 75,000-euro ($88,000) fine.