By PAUL ELIAS Associated Press Writer

SAN FRANCISCO (AP) _ Federal prosecutors said Thursday they have ”overwhelming” proof that former Olympic cyclist Tammy Thomas lied when she told a grand jury that she never used steroids, including a high-end bicycle they allege she traded for performance-enhancing drugs when she was low on cash.

The prosecutors outlined their case against Thomas in court papers as they prepare for what will likely be the first case to go to trial as part of the government’s wide-ranging steroids probe that has implicated dozens of elite athletes, including baseball stars Barry Bonds and Roger Clemens.

Eight people connected to the Bay Area Laboratory Co-Operative, or BALCO, have pleaded guilty to drug charges, perjury or obstruction, including track legend Marion Jones who admitted lying to investigators about using steroids. Lawyer Troy Ellerman received the harshest sentence _ two years in prison _ for leaking grand jury testimony of Bonds to the San Francisco Chronicle and then denying under oath that he was the source.

Bonds has pleaded not guilty to five charges accusing him of lying to a grand jury, and the Department of Justice has opened an investigation into whether Clemens lied to Congress when he testified that he never used steroids. Track coach Trevor Graham has also pleaded not guilty to lying to federal investigators.

Thomas’ trial is scheduled to begin March 24. The start, however, could be delayed because prosecutors said they need to revise the cyclist’s indictment because U.S. District Court Judge Susan Illston is concerned that too many of Thomas’ alleged false statements are lumped into too few charges. Illston ordered prosecutors to redo Bonds’ perjury indictment for the same reason.

In Thursday’s court filings, prosecutors said they will rely in part on Thomas’ body features to prove she used steroids. Similarly, they are expected to show a jury significant growth to Bonds’ head, feet and other body changes during the time he was alleged to have used steroids.

Thomas’ attorney Evan Balogh declined comment.

The prosecutors quote a doctor’s report in August 2000 suggesting that Thomas had to shave a full beard, a steroids side effect for women.

According to the government’s filing, Dr. Margaret Wierman wrote Thomas that she feared the cyclist was exposing herself to long-term health problems if she continued to ingest steroids.

”Whether or not your voice will return to normal is unclear,” the doctor wrote.

The court filing also said that urine samples Thomas provided in 2001 and 2002 while competing tested positive for steroids when retested for investigators in 2006.

Prosecutors allege that Thomas purchased ”designer” steroids, created by rogue chemist Patrick Arnold, that were made to evade detection.

Thomas told the grand jury in November 2003 that she never received steroids from Arnold, who pleaded guilty in 2006 to drug distribution charges and agreed to cooperate with the government’s investigation. Prosecutors said Arnold will testify against Thomas at her trial.

Also testifying will be Kelcey Dalton, the chemist’s live-in girlfriend at the time who said she had several phone conversations with Thomas during a three-month period several years ago. Dalton and Thomas’ conversations ”consisted of talk about weightlifting and steroids, in particular about steroids side-effects,” the government’s court filing stated.

According to the filing, Thomas offered Dalton a LeMond racing bicycle in exchange for some of Arnold’s designer steroids.

”The deal was made and Dalton still has the bicycle,” the filing stated.

The bicycle will be shown to the jury.