Tour de France champion Floyd Landis renewed his attack Tuesday on the credibility of the French lab that conducted follow-up tests on his backup urine samples and reportedly found traces of synthetic testosterone.

``If it's going to be objective, the least you could do is send it to a lab that doesn't have motivation to confirm their work in the first place,'' Landis said on CBS' ``Early Show.''

On Monday, the French newspaper L'Equipe reported Landis' ``B'' samples had traces of synthetic testosterone. Landis refused to confirm the results and said the leaking of results to L'Equipe was yet another result of unethical maneuvers engineered by those who want him stripped of the Tour title.

``Look, I won the Tour de France and I've been trying to get that message across by educating people about what happened here in the first place,'' Landis said. ``When they asked us originally to test it, first of all, we said no. It's already been tested and it's been negative. There's no purpose in testing exactly the same samples a second time.''

Landis' lawyer, Maurice Suh, said Monday he has received some documentation from the tests done on the ``B'' samples at the Chatenay-Malabry lab outside of Paris, but it was not complete.

``We need to understand fully from the lab what they did before we're comfortable about saying what they declared to be `adverse,''' Suh said.

During the 2006 Tour, Landis tested positive for elevated testosterone to epitestosterone levels after he won the 17th stage. The 31-year-old cyclist, who repeatedly has denied doping, faces the loss of his title and a two-year ban if an arbitration panel upholds the positive test.

Travis Tygart, general counsel of the U.S. Anti-Doping Agency that is prosecuting the case against Landis, said agency rules prevented him from discussing active cases.

The ``B'' samples were tested at the behest of USADA, which is trying to bolster evidence for Landis' May 14 arbitration hearing. The most recent tests used a technique that can distinguish synthetic from natural forms of testosterone, a male sex hormone.

Pierre Bordry, president of the French anti-doping agency, told The Associated Press the tests were concluded last weekend but he didn't know the result because they were sent directly to the USADA.

Landis and his lawyers contend the test results were leaked by USADA or the Chatenay-Malabry lab where the tests were conducted, and the leaks serve as another example of a ``win-at-all-costs'' strategy anti-doping agencies are using to find the cyclist guilty.

The news of Landis' positive test during the Tour, also conducted at the Chatenay-Malabry lab outside Paris, also was leaked last year.

``This represents a massive failure on the part of WADA to manage the critical fight against doping,'' Landis said of the World Anti-Doping Agency during a teleconference Monday.

Landis also complained about the restricted access given to the cyclist's experts who attended the tests last week. Most notably, Landis was upset that his expert, Paul Scott, was locked out of the lab Sunday, forced to sit on the concrete outside. Scott was supposed to be allowed in if USADA had an expert there, but USADA didn't send anyone Sunday.

``Based on this behaviour, we are looking at potentially deliberate falsification of results and the wilful destruction of evidence,'' Landis said.

Other complaints from the Landis camp include:

_ The legality of tests of ``B'' samples when the ``A'' samples already have been cleared. An arbitration panel has said there was no rule against testing the ``B'' samples but reserved the right to rule on how they can be used in evidence. The panel did confirm a positive ``B'' test could be used as corroborating evidence but not as a substitute for a negative ``A'' test.

_ The decision to conduct the tests at the Chatenay-Malabry lab that Landis has scrutinized for testing irregularities and has said might have caused his original positive test. The UCLA lab where Landis wanted the tests done wasn't available because the machine that handles carbon-isotope ratio testing there is under repair.

Landis has travelled the country to raise money for his defence and has come up with about US$500,000 in donations. He has asked for and been granted an open hearing with USADA, which is scheduled to begin May 14 at Pepperdine University.

But the recent follow-up tests on the backup samples have added new evidence for the Landis camp to dispute, and his lawyers now say they wouldn't mind a delay.

``Time is very short,'' Suh said. ``We don't have documents and results. We don't have a lot of the discovery to which we're entitled yet.''

Landis faces becoming the first rider in the 104-year history of the Tour to be stripped of the title. He already has agreed not to compete in this year's event while the case is pending.