A damning report has criticised "serious failings" in the anti-doping operation at the Rio 2016 Olympics.
The 55-page World Anti-Doping Agency Independent Observers report accused the management team in the Rio 2016 anti-doping department of "a lack of coordination", which it said contributed to putting an almost unmanageable strain on attempts to carry out drug tests.
The report said that on some days up to half of all planned tests due to be carried out in the athletes' village had to be aborted because the athletes could not be found.
The build-up to the 2016 Games was dominated by a doping scandal, with Russia not given a blanket ban from the event despite revelations of state-sponsored doping.
As well as a "lack of coordination/unified approach" among the Rio 2016 anti-doping department management, the report also blamed the failings on financial cutbacks, tensions between Rio 2016 and the Brazilian Anti-Doping Agency and significant staffing changes in the Rio 2016 anti-doping department.
The report was fiercely critical of the lack of support, training and information given to chaperones whose job it was to notify athletes of testing.
The report said: "Chaperones were often provided with little or no whereabouts information for athletes targeted for out-of-competition testing in the athletes village, and therefore, the majority of times had to resort to asking team officials and/or athletes from the same team where the athletes they were looking for were located.
"Providing the names of the athletes they were seeking was (at best) highly inefficient and obviously compromised the 'no notice' nature of the testing.
"In addition, when initial attempts to find an athlete in his or her room were unsuccessful, chaperones often lacked the training and/or the confidence to follow up with further enquiries and effort to find the athlete in other locations in the village (such as the dining hall).
"Ultimately, many athletes targeted for testing in the Athletes Village simply could not be found and the mission had to be aborted. On some days, up to 50 per cent of planned target tests were aborted in this way."
