Police have searched the home of German biathlete Evi Sachenbacher-Stehle following her positive doping test at the Winter Olympics, Germany's Sochi Games team chief said on Saturday.
The Bavarian federal criminal police office have also searched the biathlon performance centre in Ruhpolding, 120km southeast of Munich.
German team delegation chief Michael Vesper said an investigation ordered by prosecutors on Friday was concentrating on the use of food or dietary supplements.
A spokesman for the Munich prosecutor's office said the biathlon centre and two private buildings were searched to secure possible evidence. Food supplements were discovered in one building. Prosecutors are not focusing on the athlete but investigating "unknown persons" for "bringing pharmaceutical products into circulation for the purpose of doping in sport," the spokesman said.
Vesper said Sachenbacher-Stehle had used a dietary supplement containing a prohibited stimulant. She had not received it from the German team but from a mental trainer and it was "her private, personal decision" to use it.
The 33-year-old two-time Olympic cross-country relay gold medallist has been stripped of her results at the Sochi Games following the positive test.
Following a disciplinary hearing, the International Olympic Committee (IOC) said late on Friday she was retrospectively disqualified after finishing fourth in both biathlon 12.5km massed start and mixed relay events.
The IOC has asked the International Biathlon Union to remove her from the results lists, meaning the German mixed relay team also lose their fourth-placed finish.
Sachenbacher-Stehle and Italian bobsledder William Frullani were expelled by their Winter Olympic teams after testing positive for banned stimulants.
The German Olympic Association DOSB said Sachenbacher-Stehle, with five Olympics medals in all, tested positive for methylhexanamine.
Sachenbacher-Stehle has been the most successful woman on Germany's biathlon team at Sochi 2014. In the 7.5km sprint and the 10km pursuit events, she also posted the best German results with an 11th and 27th place respectively.
In a statement, Sachenbacher-Stehle said: "I am experiencing the worst nightmare you can imagine because I cannot at all explain how the positive test has come about."
Vesper said he was informed of the positive doping test in a letter from IOC president Thomas Bach. The sample was taken after the biathlon mass start.
Sachenbacher-Stehle "was shocked by the news; the mood in the team is clearly very bad," Vesper said. "We have always stood for clean sport and that is why quickly and decisively, in conjunction with the athlete's decision, we have excluded her from the Olympic team.
"We have always warned athletes about dietary supplements and the dangers they harbour. She has been taking these dietary supplements for a long time."
Frullani failed a doping test in the Olympic Village on February 18 for dymethylpentylamine. Originally used as a nasal decongestant, the substance is also found in supplements and is classified as a prohibited stimulant.
The IOC has said in Sochi it was planning to carry out 2453 tests, including 1269 pre-Games controls.