New York ? Marion Jones’ career of triumph and suspicion is back on track.

Though she probably won’t run again this year, the strongest doping allegations against her are now defunct, and her sights are firmly set on next year’s world championships – and the 2008 Olympics.

“She’s a hell of an athlete,” her coach Steve Riddick told The Associated Press on Thursday, “and I think people should just leave her alone.”

Once the darling of her sport, Jones’ successful fight against her first positive drug test is the latest twist in a career of extreme highs and lows.

“I would hope that now that it’s over with she can relax the rest of the year and come back and represent the country at the world championships, then go on to Beijing,” Riddick said.

After competing for years under a cloud of suspicion, Jones tested positive for EPO June 23 at the U.S. track and field championships in Indianapolis, where she won the 100 meters, her 14th national title.

Jones immediately requested a “B” sample be tested.

Her attorney released a statement on Wednesday that the second test was negative, a result Jones said she was “ecstatic” about.

The tests were conducted at a UCLA laboratory that routinely examines samples for the U.S. Anti-Doping Agency. Lab director Don Catlin did not return a telephone request for comment.

Riddick said he doesn’t expect Jones, who turns 31 on Oct. 12, to race again until next season, when she’ll aim for another U.S. title and a berth in the world championships in Osaka, Japan.

Arne Ljungqvist, chairman of the International Olympic Committee medical commission and a member of the World Anti-Doping Association executive committee, called the reversal of the “B” sample “quite unusual.”

“It’s happened only a handful of times in the last 30 years I can remember, but it does happen,” he said in a telephone interview with the AP. “One needs to seek an explanation from the lab. … For the time being, we can only speculate.”

In 2003, Kenyan distance runner Bernard Lagat pulled out of the 2003 world championships after news leaked that he had tested positive for EPO.

He was later cleared, though, when the “B” test was negative, and won the national 1,500-meter title in Indianapolis this year.

USA Track & Field, the sport’s national governing body, had little to say about Jones’ case.

“We respect the USADA process,” spokeswoman Jill Geer said, “and when an athlete’s ‘B’ does not confirm the ‘A’ there is no doping offense. So in Marion’s case, there is no doping offense.”

It remains unclear which test – the “A” or “B” – is accurate.

“We certainly know there are situations where the A and B may not necessarily look the same,” Ljungqvist said.

“One doesn’t know if the A is the correct analysis and the B is incorrect, or vice versa. That’s the open question.”

Jones’ negative “B” sample has done nothing to shake USADA’s faith in the testing process, general counsel Travis Tygart said.

Jones was one of the featured performers at the 2005 Kansas Relays.