Drug-free urine samples submitted by world sprint champion Katrin Krabbe and two of her German teammates came from the same person, the German athletics federation confirmed Sunday.
The federation, however, called for further investigation into the apparent drug-test tampering before making a final decision on whether to ban the athletes from competition. It also invited the three to appear before its legal committee to discuss the incident.
"We're not guilty," Krabbe said Sunday. "Others did the manipulation."
Said Dr. Manfred Donike, a leading authority on doping in sports: "All three urine tests came from the same person. I cannot say at this time from whom."
The federation said it would take up the issue in the next few days and could ban Krabbe, Grit Breuer and Silke Moeller from competition for up to four years. Falsifying drug tests carries the same penalty as testing positive for banned substances under International Amateur Athletic Federation rules.
Krabbe, 22, won the 100- and 200-meter races at last year's World Championships in Tokyo. Breuer is last year's 400-meter world championship silver medalist and Moeller is a former 100-meter world champion.