MALIBU, Calif. - Attorneys for Floyd Landis began trying to paint a picture yesterday of incompetence at the French lab where the cyclist's urine was tested.

Using computer logs from the lab, Landis' attorneys tried to prove lab workers manipulated the calibration of the machine that performed tests on the cyclist's backup samples - and claimed a U.S. Anti-Doping Agency scientist tried to prevent the Landis camp from seeing the logs.

"Because without these log files, we wouldn't know about the data that was deleted," Landis attorney Maurice Suh said.

Suh showed instances where calibration tests were performed, then rerun, and the first records of those tests were erased by the new results.

Landis is accused of using banned synthetic testosterone during his Tour de France victory last year. He appeared for the second straight day at his arbitration hearing in a yellow tie, one that matches the color of the jersey he won. A three-man panel will decide whether to uphold his positive doping test. If it does, Landis could face a 2-year ban from cycling and become the first person in the 104-year history of the race to have his title stripped.

During the Tour, Landis was tested eight times. Of those, only one tested positive. But last month, USADA asked that the backup "B" samples of his seven negative tests be subjected to carbon-isotope ratio testing to look for synthetic testosterone. Four of those seven returned with "abnormal testosterone profiles," and the Landis camp is trying to prove that is a result of mishandled tests. *