The Trinidad and Tobago athletics federation has confirmed that sprinter Kelly-Ann Baptiste is involved in a doping case and that is why she withdrew from the 100m at the world championships.
The 2011 bronze medalist had been scheduled to compete in the 100, 200 and 4x100 relay, but she pulled out of the Sunday's 100 heats.
The federation said the withdrawal was "related to doping matters,'' and it was notified on Thursday by the IAAF of the case and said it was "premature and inappropriate'' to comment further since the case was still being dealt with.
Baptiste set a national record of 10.83 seconds this year and was third in the season standings.
In the same event, 2011 silver medalist Veronica Campbell-Brown of Jamaica was suspended from competition while a disciplinary panel reviews her doping case.
Along with Baptiste, the Trinidad and Tobago federation said that Semoy Hackett was also missing from the world championships related to doping issues.
"The absence of both athletes is related to doping matters of varying degrees and complexity,'' the federation said in a written statement.
The 24-year-old Hackett served a six-month doping suspension in 2011.
Turkish doping scandals
Because of that, Trinidad and Tobago was stripped of its fourth-place finish in the 4x100 at the 2011 world championships in Daegu, South Korea.
Meanwhile, in another doping scandal, at least 16 oil wrestlers tested positive for banned performance enhancing substances, Turkish media reports said on Monday.
It was the latest in a series of doping scandals to have hit Turkish sports.
Oil wrestling champion Ali Gurbuz is among the wrestlers facing a two-year suspension from the traditional Turkish sport in which wrestlers are greased up with olive oil, according to Radikal newspaper.
The Turkish Wrestling Federation did not comment on the report but the mayor of Edirne province, where the main annual Kirkpinar oil wrestling competitions are held, told the private Dogan news agency that Gurbuz would be stripped of his title and that he would return the contest's 30,000 lira ($16,000) prize money.
Turkey's doping problems threaten to derail Istanbul's campaign to host the 2020 Olympics.
Madrid and Tokyo are also bidding to host the 2020 Games.
In the past two weeks, the Turkish Athletics Federation suspended 40 athletes for two years for doping violations. TAF is also investigating alleged doping by Asli Cakir Alptekin, the women's 1,500-meter champion at the 2012 Olympics, and two other team members.