An athlete who made doping allegations against leading coach Alberto Salazar in a BBC investigation says more people have come forward with information since the claims were broadcast.
American Kara Goucher, 36, said she was approached by "multiple" people and has urged them to go to the US Anti-Doping Agency (Usada) with their concerns.
Salazar, 56, last week issued a detailed denial of the allegations.
"I believe the truth will come out," middle distance runner Goucher said.
Speaking at a US Athletics world championships trials meeting, Goucher, who used to be coached by Salazar, added: "I had constantly all day long people passing me information and wanting me to bring it forward.
"I really want to reach out to all the people who reached out to me, to reach out to Usada. To please come forward, I pass everything along that you give me but the case is much stronger if it comes from you."
The allegations were made in a BBC documentary in collaboration with US journalism website ProPublica.
It was claimed that Salazar violated various anti-doping rules and used testosterone medication on American long-distance runner Galen Rupp in 2002 when he was 16.
The BBC understands Salazar is being investigated by Usada to determine whether anti-doping rules may have been violated.
Both Salazar and Rupp, who was the silver medallist in the 10,000m at the London 2012 Olympics, deny all the allegations.
|Who is Alberto Salazar?|
|Born: Havana, Cuba (emigrated to US as a child)|
|Achievements: Three-time New York Marathon winner (1980, 1981, 1982), Boston Marathon winner (1982), US Outdoor Track & Field 10,000m champion (1981, 1983), US Cross Country Champion (1979), National Distance Runner's Hall of Fame inductee (2000), represented US at 1984 Olympics in LA|
Salazar has issued a 12,000-word rebuttal, backed by emails and other documents, saying he "will never permit doping" at his Nike Oregon Project training base.
Salazar's former assistant, Steve Magness, said the American coach's lengthy response to claims in the BBC investigation "reeks of desperation".
However, British athlete champion Mo Farah, who trains with Salazar, has said he will remain with the coach. There is no suggestion the world and Olympic 5,000m and 10,000m champion has broken any rules.
Speaking at the same meeting as Goucher on Sunday, Rupp said he "had nothing to hide" and would "do whatever I need to do to co-operate with" Usada.