In February, Contador was stripped of his 2010 title after losing a drawn-out court battle with the International Cycling Union and World Anti-Doping Agency. The ruling came just three days after U.S. federal prosecutors dropped a doping investigation involving Armstrong. The American was a teammate of Contador during the Spaniard's 2009 Tour victory.
Contador's spokesman said the Spanish rider no longer worked with Marti and that their previous relationship was limited to being teammates.
"This is a coincidence of him (Contador) being on the teams for which he (Marti) worked," Jacinto Vidarte told The Associated Press. "It has nothing to do with what has happened. That period of when he was with the team is over."
Cycling's governing body, the International Cycling Union, which collected the 2009 and 2010 samples cited in the USADA letter, said it was not involved in the anti-doping group's investigation.
According to USADA's letter, more than 10 cyclists as well as team employees will testify they either saw Armstrong dope or heard him tell them he used EPO, blood transfusions, testosterone and cortisone from 1996 to 2005. Armstrong won the Tour de France every year from 1999-2005.
During their investigation, federal prosecutors subpoenaed Armstrong supporters and ex-teammates to testify in Los Angeles. One of the most serious accusations came during a "60 Minutes" interview when former teammate Tyler Hamilton said he saw Armstrong use EPO during the 1999 Tour de France and in preparation for the 2000 and 2001 tours.
Early in the criminal investigation, Armstrong attorney's accused USADA of offering cyclists a "sweetheart deal" if they would testify or provide evidence against Armstrong.
In a letter to USADA last week, Armstrong attorney Robert Luskin noted that USADA Chief Executive Officer Travis Tygart participated in witness interviews with federal investigator Jeff Novitzky during the criminal probe.
"It is a vendetta, which has nothing to do with learning the truth and everything to do with settling a score and garnering publicity at Lance's expense," Luskin wrote.
In a statement, Tygart said, "USADA only initiates matters supported by the evidence. We do not choose whether or not we do our job based on outside pressures, intimidation or for any reason other than the evidence."
Armstrong has until June 22 to file a written response to the charges. The case could ultimately go before an arbitration panel to consider evidence. The USADA letter said in that case a hearing should be expected by November.
Associated Press writers Joseph Wilson in Barcelona, Spain, and Victor L. Simpson in Rome contributed.
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