French police carried out searches as they targeted the Bahrain Victorious team in Pau ahead of stage 18 of the Tour de France.
The reason for the raid on the team hotel has not been announced.
Team chiefs confirmed officers requested training information and searched rooms of the cyclists.
A Bahrain Victorious statement read: "On the eve of stage 18 of Tour de France, Team Bahrain Victorious were subject to an investigation by French police. The team were monitored by a number of officers following their arrival after stage 17 to the team hotel in Pau.
"The investigation involved a search of riders' rooms as part of the process. Despite being unaware of the investigation reasons, the team was also requested to provide all training files which were compiled and presented to the officers as requested."
Technical director Vladimir Miholjevic stressed there had been no wrongdoing on the part of the team and said the police action had been a disruption to planning for Thursday's stage.
He said: "Following stage 17, we were greeted by several French police officers. We were not given a warrant to read through, but the team complied with all the officers' requests.
"We are committed to highest level of professionalism and adherence to all regulatory requirements and will always be cooperating in a professional manner.
"The process had impacted our riders' recovery and meal planning and as a professional team, the well being of our team is a key priority."
The team's highest-ranking rider overall in this year's tour is Peio Bilbao, who sat 10th in the individual general classification going into Thursday's journey from Pau to Luz Ardiden.
Wouter Poels held top spot in the king of the mountains rankings, while Sonny Colbrelli was third in the points standings.
Bahrain Victorious, who had stage wins earlier in the Tour by Matej Mohoric and Dylan Teuns, stood collectively in first place in the team classification.
