O.J. Trial Focuses on Audio Evidence

Robert Lucherini, a lawyer for Stewart, has already challenged the conclusions of FBI audio examiner Kenneth Marr, whose testimony began Tuesday via videotape about enhancing recordings made by collectibles broker Thomas Riccio.

Lucherini said in documents filed this month with the Nevada Supreme Court that Marr, whose testimony was taken Aug. 25, could not authenticate the recordings.

Riccio is waiting in a downtown Las Vegas hotel to testify about arranging the meeting between Simpson, Stewart and two memorabilia dealers a year ago.

"They told me, 'Anytime from late Tuesday to early Thursday,'" Riccio told The Associated Press by telephone Tuesday. He said prosecutors told him to expect to be on the stand for as long as a day and a half and also asked him to "refrain from talking before I testify."

"I hope they don't just have to go by what I say," added Riccio, who said he gave authorities more than 10 hours of audio recorded before, during and after the Sept. 13, 2007, alleged armed robbery. "All they have to do is listen to my tapes."