SAN FRANCISCO (AP) – The lead investigator in the government’s wide-ranging steroid distribution probe testified Monday that former elite cyclist Tammy Thomas made extra work for investigators when she allegedly lied to a grand jury when she denied using steroids.

Thomas has pleaded not guilty to making false statements and obstruction of justice.

Her trial entered its second week Monday with her lawyer questioning IRS agent Jeff Novitzky about what effects the former cyclist’s 2003 grand jury testimony may have had on the government’s investigation of performance enhancing drug use among elite athletes. In order to be convicted, the jury hearing the case will have to find that not only did Thomas lie, but that the alleged lies hindered the government’s investigation.

Thomas denied she received designer steroids from chemist Patrick Arnold, who pleaded guilty to creating the designer steroids that Thomas and Major League Baseball home run king Barry Bonds are accused of taking.

Bonds, who is still a free agent, is also charged with perjury for allegedly lying to the same grand jury about never knowingly using performance-enhancing drugs.

Two of Bonds lawyers watched most of Novitzky’s testimony. Novitzky is expected to testify during a Bonds trial.

Novitzky said Thomas’ denial that she received designer steroids from Arnold prompted investigators to consider that other steroid makers existed.

“We looked into other sources,” Novitzky said.

Ultimately, Novitzky said it turned out that a pharmacist in Texas was making the designer steroids created by Arnold for the Burlingame-based Bay Area Laboratory Co-Operative, known as BALCO, where the elite sports drug ring was centered.

Eight people connected to BALCO, including track diva Marion Jones, have pleaded guilty to drug charges or perjury. Thomas is the first to go to trial.

Novitzky said 30 athletes were called to testify before the grand jury in 2003.

Novitzky didn’t identify any of the athletes, but testified there was “some evidence” that professional wrestler Bob Sapp – who briefly played in the NFL – bought steroids from Arnold.

Novitzky is expected to finish testifying Tuesday morning and prosecutors plan to next call sports doping expert Don Catlin to the witness stand.

Catlin has developed numerous tests to detect performance-enhancing drugs and helped expose hundreds of cheating athletes. He discovered both of Arnold’s previously undetectable steroids – THG and norbolethone – that are at the heart of the BALCO investigation.

Thomas was banned from competition in August 2002 after norbolethone was found in her urine. Thomas’s positive result was the first discovery of an elite athlete taking the so-called “designer drugs.”

In a pre-trial hearing, Thomas’ lawyers said the cyclist was telling the truth during her grand jury testimony because norbolethone wasn’t classified as a steroid at the time.

Norbolethone was originally tested by Wyeth Laboratories in human trials during the 1960s as a potential treatment to help severely short people grow and for conditions causing weight loss. The company abandoned development of the steroid in the early 1970s and it was never marketed.

It languished in obscurity until Arnold dusted off Wyeth’s recipe and made new batches to boost athletic performance.

The United States Anti-Doping Agency wasn’t testing for the steroid until Catlin determined Thomas had used it.

AP-ES-03-31-08 2015EDT