According to the Associated Press, Mike Anderson made the claim in a brief filed in state district court.
Lance Armstrong has said on many occasions that he has never taken any banned substances and is one of the most drug-tested athletes in the world.
Anderson alleges he was cleaning the bathroom of Armstrong's Girona apartment in early 2004 when he found a white box labelled with the trademark name Androstenine, or something very close to this, said Anderson
This is androgen, a listed banned substance.
He was torn about what to do. Hes an honest guy opposed to doping in sports, said Andersons attorney, Hal Gillespie. [But] he was sure that if he confronted, he would be fired."
Associated Press reports that Gillespie said Anderson did not see Armstrong taking any banned substances.
Anderson started working for Armstrong in 2002 and was fired in 2004. Armstrong and his personal service company, Luke David LLC, sued Anderson shortly after he was fired, claiming Anderson demanded Armstrong pay him $500 000, give him a signed Tour de France jersey and provide endorsements to help him set up his own bike shop.
Anderson countersued, accusing Armstrong of fraud, breach of contract and causing him emotional distress.