The Kenyan runner exceeded Ethiopian record holder's female marathon world record by nearly 120 seconds at the Chicago Marathon in the year 2024.
Female long-distance world record-holder Ruth Chepngetich has been banned for three years after the runner admitted to doping infractions.
The record holder was temporarily banned in July following a positive test for a banned substance - a prohibited substance used commonly as a concealing drug - on March 14.
The athlete's accomplishments which pre-date that sample - including her world record performance of 2:09:56 in Chicago in 2024 - will still stand.
The sports governing body had sought a 48-month ban but the 31-year-old punishment was lowered to 36 months because she admitted to the infractions.
However, the AIU will keep examining evidence from the athlete's phone which it found indicate "strong grounds that her positive test may have been deliberate" - featuring messages from as early as 2022.
"This matter regarding the failed test for HCTZ has been resolved, but the AIU will keep looking into the questionable evidence found on Chepngetich's phone to determine if any further infractions have taken place."
When interviewed in April by the AIU, the marathoner, the first woman to run a marathon in under 2:10, was unable to give an reason for the failed test.
Although HCTZ has a minimum reporting level of 20 nanograms per millilitre (ng/mL) in urine, the athlete's sample showed an estimated concentration of 3800 ng/mL.
Traces of the diuretic under the detection threshold were also identified in a sample collected from the runner 14 days prior, on February 28.
At a subsequent meeting on July 11, the record holder was shown the previously mentioned suspicious evidence acquired from her mobile. In the meantime, accidental exposure had also been ruled out by the AIU.
The athlete altered her story on July 31, claiming that she had used her housemaid's medication - labeled as being HCTZ - after falling sick two days before the failed test.
The AIU had "serious reservations about the credibility of the new version of events" and, in the framework of the athletics' doping regulations, such "recklessness" is deemed "indirect intent, for which an increased four-year sanction is applicable".
An standard 12-month decrease was applied after the runner confessed to the doping breaches within the specified 20-day period.
The three-year ban started on April 19 - when Chepngetich agreed to a temporary ban - with the runner's results, awards, championships, participation and prize money from March 14 lost.
"Nobody is exempt from regulations."
"While unfortunate for those who had faith in this athlete, this is how the process is supposed to work."
"Marathon organizers should be praised for jointly supporting anti-doping efforts capable of revealing doping violations committed by elite athletes in their events."
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