Mo Farah has been warned by a tearful former team-mate that more revelations about Alberto Salazar are in the pipeline and he risks tarnishing his reputation if he stays with the coach. On a day when Farah pledged to speak under oath to the United States Anti-Doping Agency, Kara Goucher – who trained alongside Farah in 2011 and 2012 – refused to criticise him directly but urged anyone thinking of training with Salazar to “think long and hard because you’re going to be labelled something for the rest of your life”.

Goucher, one of the whistleblowers in the BBC Panorama programme, also said she was confident Usada would find enough evidence for “the truth to come out” but admitted it would probably not happen overnight.

“I know that these things take time,” she added. “I saw Lance Armstrong on Oprah, and afterwards [the Usada CEO] Travis Tygart was on. I told my husband Adam: ‘You get me that guy and I’ll talk to him.’ Seven days later I was in his office. I believe that Usada is doing everything in its power. Think of how long it took for Lance. I believe the truth will come out. When? I don’t know.”

Goucher’s claims came a day after it was revealed Usada’s team of detectives, who brought down Armstrong in 2012, has put its investigations into Salazar and Farah’s training partner Galen Rupp on a more formal footing by interviewing the Oregon Project athlete Treniere Moser. On Sunday night Salazar promised to co-operate with Usada if it decides to question him, saying: “Absolutely, I’ve got nothing to hide.” However, when asked whether he would do so under oath, he said: “I don’t understand exactly what that means. I’d need to speak to my lawyer.” When told it would mean if he lied then he would be in trouble, Salazar repeated: “I would have to speak to my lawyer about that.”

Usada is also expected to speak to other members of the Oregon Project and its investigation may even involve senior figures at UK Athletics, which employs Salazar as a consultant. There is no suggestion Farah has committed any wrongdoing and he has made it clear to friends he would be happy to speak to any relevant authority, at any time, in any circumstances.

Goucher, the 2007 world 10,000m bronze medallist from the US, said “multiple sources” had come forward since the Panorama documentary aired at the start of June. In the programme Goucher alleged Salazar had coached Rupp to try to get a Therapeutic Use Exemption (TUE) for an intravenous drip before the 2011 world championships and had offered her a thyroid drug to get her to lose weight. In his 11,750-word response to the BBC’s claims last week Salazar called both claims false and published detailed email documentation that appeared to show he was happy with Goucher’s weight.

Yet Goucher stands by her story and says there is more to come. “I have, constantly, all day long, people passing me information, wanting me to bring it forward,” she said.

“I really want to encourage all the people who have reached out to me to reach out to Usada. I pass everything along that you give me but the case is much stronger if it comes from you.

“I will most definitely give all my evidence in the coming days. They took my quotes out of context and when you put partial emails or emails from a 10-email-long chain and just put one in, you don’t get both sides. I understand that, if you read it through, it looks like I’m a liar. I don’t like being labelled a liar, just like anybody else.”

Goucher insisted she would continue to fight for a clean sport despite Salazar’s ferocious counterattack on her character. “I’m being dragged through the mud and it will probably continue but I’m still here, I’m going to keep racing and I stand by my statements and I always will. I want my son to be able to believe in the sport and the system.” Goucher, who first spoke to Usada in February 2013, also confirmed that she would be happy to go under oath. “I would welcome that opportunity for myself, for every former Oregon Project member, for every doctor that’s been involved,” she said.

Rupp, who finished third in the final of the 5,000m on Sunday, said he had sent Usada “tons of documents and had nothing to hide”. He added: “Usada knows everything. I’ll do everything I need to do to co-operate with them.”

Rupp’s team-mate Matthew Centrowitz, who won the 1500m at the US trials on Saturday, insisted he had never seen any evidence of wrongdoing at the Nike Oregon Project. ‚ÄúIf I ever saw one thing that I felt was wrong or whatever I would be the first to leave,‚Äù he added.

The most impressive time of the final day of the trials came from the controversial sprinter Justin Gatlin, who became the fifth fastest man in history over 200m when he ran 19.57sec.

The most impressive performance, however, came from Alysia Montaño, who won the 800m only 10 months after giving birth to a daughter. Montaño ran in last year’s championships when she was pregnant.