LeMond, who won the Tour de France three times, testified Thursday at the U.S. Anti-Doping Agency hearing into Landis' positive test during last year's race.
LeMond, who was sexually abused as a child by a family friend, said he revealed his secret in the hope that if Landis, too, had a secret to share that Landis would reveal it, NBC reported.
Landis' business manger, Will Geoghegan, was fired immediately after LeMond testified that he had received a harassing phone call from Geoghegan threatening to reveal that Lemond had been abused, NBC reported.
"I have to say that what his manager said to me (Wednesday) was one of the most vicious and mean-spirited things ever done to me," LeMond said in a telephone interview with NBC Thursday night.
LeMond said he told Landis about the abuse last summer after Landis won the Tour de France. It is not known whether Landis knew about Geoghegan's alleged phone call. The Los Angeles County Sheriff's Department is investigating the incident.