Marion Jones admitted using steroids before the 2000 Olympics in a recent letter to close family and friends, The Washington Post reported Thursday.
Jones, a triple gold medalist in Sydney, said she took "the clear" for two years, beginning in 1999, and that she got it from former coach Trevor Graham, the newspaper reported. Graham told her it was flaxseed oil.
"The clear" is a performance-enhancing drug linked to BALCO, the lab at the center of the steroids scandal in professional sports.
Jones had steadfastly denied she ever took any kind of performance-enhancing drugs.
Jones is scheduled to appear in U.S. District Court in White Plains, N.Y., on Friday to plead guilty to charges in connection with her steroid use, a federal law enforcement source told The Associated Press. The official spoke on condition of anonymity because the investigation is ongoing, and would not provide specific details about the plea.
"I want to apologize for all of this," the Post reported Jones saying in her letter, quoting a person who received a copy and read it to the paper. "I am sorry for disappointing you all in so many ways."
Jones said in her letter that she faced up to six months in jail and would be sentenced in three months, according to the newspaper.
"Red flags should have been raised when he told me not to tell anyone," the Post reported, quoting the letter.
No one answered the door at Jones' Austin, Texas, home Thursday night, and a message left by the AP for a phone number registered to her husband, Obadele Thompson, was not immediately returned.
The admission could cost Jones the five medals she won at the Sydney Olympics. Though she fell short of her goal of winning five gold medals, she came away with three and two bronzes and was one of the Games' biggest stars.
But her career has been tarnished by doping allegations since then. Victor Conte, head of the Bay Area Laboratory Co-Operative, repeatedly has accused Jones of doping.
Speaking to ESPN.com's Mike Fish on Thursday, Conte reiterated his claim that Jones cheated her way to Olympic success by using the oil known as "the cream" and arthritis balm commonly called "the clear."
"What I said in December of 2004 is that Marion Jones had used the cream and the clear -- that was a true statement," he said. "I'm here today saying the same thing again -- that before during and after the Olympic Games in 2000 that Marion Jones used [performance-enhancing drugs]."
Jones sued Conte in 2004 for $25 million after he told a national television news program that the sprinter used designer steroids, human growth hormone and other illegal performance enhancers before and during the 2000 Summer Olympics in Sydney.
Conte said he taught Jones how to inject human growth hormone during a track meet in 2001. He said he also held conference calls with Jones and Graham where the three of them discussed Jones' "doping" regimen.
"Jones has never taken banned performance enhancing drugs," the sprinter alleged in her defamation lawsuit. "Jones took and passed over 160 separate drug tests, including five different drug tests at the 2000 Olympics."
The pair settled the lawsuit in 2005 for an undisclosed amount.
Jones was one of several athletes, including home run king Barry Bonds, New York Yankees slugger Jason Giambi and Detroit Tigers outfielder Gary Sheffield, to be linked to BALCO and were among more than two dozen athletes who testified before a federal grand jury in 2003.
According to grand jury transcripts obtained by the San Francisco Chronicle, Bonds said he thought two substances given to him by trainer Greg Anderson were flaxseed oil and an arthritic balm. Authorities suspect those items were actually BALCO-linked "the clear" and "the cream.
In her letter, Jones said she didn't realize she'd used performance-enhancing drugs until she stopped training with Graham at the end of 2002. She said she lied when federal agents questioned her in 2003, panicking when they presented her with a sample of "the clear," which she recognized as the substance Graham had given her.
"It's funky, because you wanted to believe she was clean," said Jon Drummond, a gold medalist in the 400 relay in Sydney. "It's like that old saying, 'Cheaters never win.' So no matter how glorious or glamorous things look, you'll get caught and pay a price for it.
"It caught me by total surprise," he added. "It's a shock. I thought it was a closed case. It doesn't help track and field at all, except maybe by letting the world know, people always get to the bottom of things. We shouldn't be afraid of the truth, but it's sad it came to this."
Jones' career has been tarnished the last several years by doping allegations against her. In August 2006, a urine sample tested positive for EPO, but Jones was cleared when a backup sample tested negative.
She also was among the athletes who testified before a BALCO grand jury in 2003. Her former boyfriend, Tim Montgomery, also testified, and was given a two-year ban for doping in late 2005. Michelle Collins and Justin Gatlin, who also trained with Graham, were banned for doping violations, too.
Graham has a Nov. 26 trial date after being indicted in the BALCO case last November on three counts of lying to federal agents. Graham, who has pleaded not guilty, helped launch the government's steroid probe in 2003 when he mailed a vial of "the clear" -- previously undetectable -- to the U.S. Anti-Doping Agency.
A woman who answered the phone at Graham's home in Raleigh, N.C., declined to identify herself, but said Graham was not home before refusing to answer any other questions. There was no answer at the door of Graham's north Raleigh home.
USA Track & Field was not aware of Jones' letter nor any pending legal action, CEO Craig Masback said.
"Anything that exposes the truth about drug use in sport is good for ensuring the integrity of sport," Masback said. "Any use of performance-enhancing substances is a tragedy for the athlete, their teammates, friends, family and the sport."
Darryl Seibel, spokesman for the U.S. Olympic Committee, declined comment on whether Jones would lose her medals until legal proceedings are completed.
"If these reports are true," Seibel said, "it is an admission of responsibility from an athlete who owed her sport and the Olympic movement much better."
Seibel added that "our position on doping is unequivocal. Doping is cheating, and under no circumstance will it be tolerated. If an athlete cheats, they deserve to pay the price for their action."
The Post also reported that, in her letter, Jones said she lied about a $25,000 check given to her by Montgomery, who pleaded guilty in New York in April as part of a criminal scheme to cash millions of dollars worth of stolen or forged checks. He has yet to be sentenced.
Wells, Jones' longtime agent, and Olympian Steve Riddick, another of Jones' former coaches, also were convicted in the scam.
Bank records indicated Jones had received a $25,000 check from one of the alleged conspirators -- Nathaniel Alexander, who shared office space with Riddick and also was convicted. The check never cleared, according to records, and Jones was never charged.
"Once again, I panicked," the Post reported, quoting Jones' letter. "I did not want my name associated with this mess. I wanted to stay as far away as possible."
In her prime, Jones was one of track's first female millionaires, typically earning between $70,000 and $80,000 a race, plus at least another $1 million from race bonuses and endorsement deals.
In 2000-01, she competed in 21 international events, including the Sydney Olympics, where she won five medals -- three gold.
Information from The Associated Press and ESPN.com's Mike Fish was used in this report.