The doping charges brought against Bahrain's 400 metre world champion Salwa Eid Naser have been dismissed, the Athletics Integrity Unit announced on Tuesday.
The 22-year-old Naser was provisionally suspended in June and charged with failing to meet 'whereabouts' criteria in circumstances the World Athletics Disciplinary Tribunal said "would have been comical were the consequences not so serious".
The AIU charged the Nigerian-born runner with four alleged 'whereabouts' failures which included three missed tests between March 2019 and January this year.
But the Disciplinary Tribunal ruled that one of those, on April 12, 2019, "cannot be confirmed" as a missed test by the athlete, meaning Naser had not missed three tests within 12 months which is required to prove an anti-doping violation.
The tribunal reported problems with the online whereabouts system 'ADAMS' for both sides.
It said that Naser had never managed to log on to ADAMS let alone submit her whereabouts information. The Bahrain athletics federation had delegated the task to one of its officials, who failed to update Naser's whereabouts for a test in January of this year after sleeping through the morning deadline to update her location.
The tribunal rejected Naser's assertion that this should not count as a missed test.
For the earlier test, last April, the tribunal ruled that even though Naser's ADAMS information gave the wrong address, the inspector should have done better once he had worked out the correct building.
"What happened next would have been comical were the consequences not so serious," said the ruling.
The inspector, Enrique Martinez, turned up at 6:00 am and was reluctant to wake anyone other than Naser.
He first mistook a parking place number for a door number and knocked for five minutes on a store room. He did not realise that the apartment block intercom did not work or that, for that reason, the outside door had been left unlocked.
In the last five minutes of the designated hour, the tester is allowed to phone, but Naser's number on ADAMS was wrong.
Naser, meanwhile, was where she said she would be, asleep in her flat. Because Martinez never managed to reach her door, she did not, the tribunal ruled, miss the test.
The Naser ruling is a further blow for the whereabouts rules in the anti-doping fight.
The problems have been highlighted by the long-running saga of US sprinter Christian Coleman who appealed one ban for missing three tests so he could run in the 2019 World Championships, where he won 100m and 100m relay golds, but was in June provisionally suspended again.
At the same world championships in Doha, Naser, who improved by a second a season from 2016-19, stunned athletics when she powered to the third-fastest 400m in history to take the title.
Her time of 48.14 seconds has only been bettered by East German Marita Koch and former Czech runner Jarmila Kratochvilova in the 1980s.
The AIU is the independent anti-doping watchdog for track and field, set up in 2017.
It has the right to appeal the verdict to the Court of Arbitration for Sport.