Former Olympic champion Marion Jones tested positive for the banned blood-boosting drug erythropoietin at the 2006 U.S. Track and Field Championships in June, according to Chicago Tribune sources.
The positive EPO result came from the "A" sample test on her urine. The "B" sample is scheduled to be tested Sept. 6, according to a source familiar with the case.
Jones' test was performed on a sample given after she won the 100 meters on June 23 in Indianapolis, her 14th national championship but first sprint title since 2002.
She finished in 11.10 seconds, just ahead of reigning world champion Lauryn Williams.
The American sprinter would be charged with a doping violation only after the second half of her sample is tested and the result confirmed. She would face a two-year ban from track and field.
Jones, 30, who won three gold medals and five total medals at the 2000 Olympics, had faced allegations of doping related to the Bay Area Laboratory Co-Operative scandal, but was never charged with doping.
She repeatedly has denied having used performance-enhancing drugs.
This season, Jones appeared to have revived a career that was in steep decline since the birth of her son June 28, 2003, and reports linking her to the BALCO scandal in 2004.
She failed to make the 2004 Olympic team in the 100 meters, which she had won at the 2000 Games and dominated from 1997 through 2001. Her best time in the 100 last year was 11.28 seconds, more than a half second from her personal best.
This year, she had broken 11 seconds twice, topped by a 10.92 in Paris on July 8.
Should Jones be charged with a doping violation, she would become the third star American athlete to face such charges in the past month. Cyclist Floyd Landis tested positive for exogenous testosterone after winning the Tour de France.
Sprinter Justin Gatlin, a three-time Olympic medalist who shares the world record in the 100 meters, tested positive for a steroid at a track meet in April.
Earlier yesterday, Jones pulled out of a scheduled appearance at a Golden League meet in Zurich, Switzerland.
Jones "received a phone call from the United States this morning and left for personal reasons," Hansjorg Wirz, the meet organizer and head of the European Athletics Association, told the Associated Press.
Wirz said that she was already on a plane home when she called to withdraw.
Jones was not invited to this year's Golden League final in Berlin on Sept. 3 because of links to former coach Trevor Graham, who is under investigation by track and field's ruling body and the U.S. Anti-Doping Agency. Other athletes who trained under Graham also were not invited.
Graham is the coach of Gatlin, who faces a lifetime ban for his failed drug test. Several other athletes coached by Graham have been suspended for doping.
Because the test came out of a U.S. meet, the results will be handled by the USADA.
Philip Hersh writes for the Chicago Tribune.