India's dope cloud in the Rio Olympics build-up continued with indications that 200m runner Dharambir Singh has returned positive for a banned substance in an in-competition test conducted last month.Dharambir, who became the first Indian male sprinter to qualify for the Olympics after 36 years, missed his flight to Rio last night, amid speculation that he had tested positive for an anabolic steroid in his A sample taken by National Anti-Doping Agency (NADA) during the Indian Grand Prix Meet in Bangalore on the 11th of July.However, neither NADA nor the Athletics Federation of India confirmed whether the athlete had flunked a dope test.He was earlier stripped of his gold medal won in 100m race during the National Inter-State Championships in 2012 for evading a mandatory dope test and a lengthy ban may bring an end to his career.Earlier, shot putter Inderjeet Singh and wrestler Narsingh Yadav had also flunked dope tests, but the latter was cleared by the NADA's Anti-Doping Disciplinary Panel which ruled that he had been victim of sabotage.