Laura Muir admits she has her "doubts" that the 1500 metres final at the Rio Olympics was a completely clean race.
The Scot came home seventh in the race at Rio's Olympic Stadium on Tuesday night as Kenya's Faith Kipyegon took gold ahead of Ethiopian world record holder Genzebe Dibaba.
Dibaba's coach is Jama Aden, arrested in June as part of an anti-doping investigation, and the 25-year-old was quizzed repeatedly on her association with him at the medallists' press conference.
The women's 1500m final at London 2012 has been dubbed the 'dirtiest race in history', with Turkish winner Asli Cakir Alptekin among a host of athletes in the race to fail drugs tests.
Great Britain's Lisa Dobriskey, who raced that day, was accused of bitterness for saying in the immediate aftermath she did not feel she was "competing on a level playing field". Instead she was proved right.
And Muir made her feelings clear in the aftermath of the Rio race.
Asked if she had confidence it was completely clean, she said: "I have my doubts, let me say that."
Her team-mate Laura Weightman, who ran in the 2012 final and finished 11th on Tuesday, said: "This final was much better than in London, but at the time of London I was only 21 and I didn't really know what was going on.
"My eyes have been opened a lot more in the last few years. But that was a much better final. I'm delighted for the medallists there - Faith Kipyegon and (American) Jenny Simpson getting a bronze."
Put to her that she did not mention Dibaba, she did not reply.
Dibaba, the 25-year-old world champion, has never failed a drug test, but her relationship with Somalian coach Aden has led to awkward questions.
The Somalian, with whom Mo Farah and British Athletics have also been forced to deny links, was arrested at a hotel in Sabadell, near Barcelona, as part of a joint anti-doping operation by Catalan police, world athletics' governing body the IAAF and the Spanish anti-doping agency and taken into custody.
Dibaba insisted she was "crystal clean" and vowed to ditch Aden if any allegations were proven.
"The world knows my coach is purely for my training," she said, speaking through an interpreter.
"The rumours roaming the world are deeply affecting my training and my competition. And this adversely affected my performance and psychological condition. I had blood and urine (taken) four, six, eight times this year. I assure you I am crystal clean.
"He (Aden) is under IAAF custody, the evaluation is undergoing. If he is clean, I will stay with Jama. If things are worse, I will stop."