Banned anabolic steroids have been found in premises used by the man who coached Kostas Kenteris and Ekatherina Thanou, according to reports.
Tzekos coached Kenteris and Thanou to medals in Sydney
Boxes of a "non-approved substance" and steroids were discovered in premises used by Christos Tzekos, said Greece's public pharmaceutical watchdog.
Greek officials are continuing to probe Tzekos, Kenteris and Thanou after the sprinters both missed a drugs test.
Kenteris, who has split with Tzekos, says he and Thanou have not used drugs.
But officials are continuing to investigate the circumstances surrounding the duo's missed drugs test on the eve of the Olympics and raided premises used by Tzekos's dietary supplements business.
The duo claimed they were injured in a motorcycle
accident hours after failing to make themselves available for the tests and later withdrew from the Games.
Kenteris claimed gold in the 200m and Thanou won a silver medal in the 100m in Sydney four years ago while being coached by Tzekos.
But last year Tzekos was fined by Greece's public pharmaceutical watchdog for importing prohibited drugs into Greece.