Tsekos, a former nutritional supplements salesman who lives alternatingly in his native Greece and his adopted home in Lincolnwood, Illinois (a suburb of Chicago), had been involved in a number of doping-related incidents before.
However, the doping controller, Klaus Wengoborski, arrived with no identification and without a female official accompanying him, a violation of IAAF regulations at the time.
In 2003, it was reported that U.S. authorities found e-mails by Victor Conte addressed to Tzekos while searching BALCO (Bay Area Laboratory Co-operative), the California company secretly dealing Tetrahydrogestrinone, an anabolic steroid specially designed so as to make it undetectable under normal drug testing.
In addition, according to the respected French paper "L'Equipe," Tzekos was directly dealing with the creator of norbolethone and THG (tetrahydrogestrinone) Patrick Arnold, the father of pro-hormone craze and some undetectable designer steroids.
[2] Tzekos has also continued to insist that he only knew Patrick Arnold as a supplier of nutritional supplements, and has denied receiving illegal substances from him.