By Laird Harrison
SAN FRANCISCO (Reuters) - Prosecutors rested their perjury case against baseball's home run king Barry Bonds on Tuesday after a laboratory chief testified that a urine sample that Bonds submitted tested positive for banned performance-enhancing drugs.
Don Catlin, the former director of a University of California, Los Angeles (UCLA) laboratory, was the government's final witness after two weeks of testimony designed to show that Bonds knowingly used anabolic steroids, muscle-building drugs.
Bonds' lawyers are expected to begin calling defense witnesses on Wednesday. It is still unclear whether the slugger, who last played in the major leagues in 2007, will take the stand.
"If Mr. Bonds testifies, it will be tomorrow," Bonds attorney Allen Ruby said on Tuesday.
Bonds has pleaded not guilty to perjury charges stemming from his denial to a grand jury investigating illegal use of performance-enhancing drugs in sports that he had ever knowingly taken steroids. Prosecutors say they will prove their case by showing that he did take steroids.
Describing a test performed on a urine sample that Bonds gave in 2003, the bald, grandfatherly Catlin said the sample contained both tetrahydrogestrinone (THG) -- a steroid that prosecutors say was designed to avoid detection -- and clomiphene -- which suppresses the hormone estrogen, potentially increasing the production of testosterone.
MORE SOPHISTICATED TEST
The sample was at first found negative by Quest Diagnostics. But an Internal Revenue Service agent seized it as part of the agency's investigation into the Bay Area Laboratory Co-operative (BALCO) and took it to the UCLA lab.
There, a more sophisticated test detected the drugs, Catlin testified.
Bonds hit 762 home runs, more than any other player in the history of Major League Baseball. While playing for the San Francisco Giants, Bonds broke Hank Aaron's 33-year-old career home run record in August 2007. Three months later, a grand jury indicted him on charges of perjury and obstruction of justice.
Bonds told the grand jury he did not knowingly use steroids or human growth hormone and said he never questioned the flaxseed oil, vitamins, protein shakes and creams his trainer supplied him.
Also on Tuesday, prosecutors submitted the transcript of a tape recording in which Bonds' doctor appears to discuss illegal steroids with Bonds' friend Steve Hoskins.
Prosecutors say the tape lends credence to testimony by Hoskins earlier in the trial that he talked frequently with the doctor about steroids. But U.S. District Court Judge Susan Illston ruled that the jury should not be made aware of the tape's existence because it was produced too late in the trial.
The case in U.S. District Court, Northern District of California is United States of America v. Barry Lamar Bonds, 07-cr-732.
(Editing by Will Dunham)