World 100 metres champion Christian Coleman has been given a two-year ban from athletics for missing three drugs tests in the space of 12 months.
The American, who has the right to appeal against the ruling made by the Athletics Integrity Unit (AIU) at the Court of Arbitration for Sport (CAS), stands to miss the Olympic Games in Tokyo next year.
The 24-year-old was provisionally suspended in June for whereabouts failures but disputed the third of those. He took responsibility for the first missed test on January 16, 2019 and claimed the second, on April 26 of the same year, was due to "a filing failure".
Coleman said he was only notified of the third missed test on December 10, the following day. He said he had been out Christmas shopping but returned during the one-hour window to be tested and questioned why he was not contacted by telephone by the tester.
In a lengthy Twitter post, he said: "I've been contacted by phone literally every other time I've been tested. Literally, Idk [I don't know] why this time was different.
"He even said he couldn't hear the doorbell so why wouldn't you call me? Why would AIU tell him not to contact me? He put down the wrong address btw [by the way] so who knows if he even came to my spot.
"That night I have multiple receipts of going shopping then getting food and coming back during this time, so I don't think he stayed for an hour and WHY WOULD AIU TELL HIM NOT TO CALL ME?!
"The AIU has to stop playing, man. Two days later they came back to test me…and followed the normal protocol and called and of course there were no issues with my test. And I've been tested multiple times since, even during quarantine.
"But of course that doesn't matter, and the fact that I have never taken drugs doesn't matter."
However, a tribunal rejected Coleman's defence that he returned home within the one-hour period, citing shopping receipts showing he purchased 16 items from a Walmart after the time slot.
"We regret to say that we do not think there is any mitigation which can fairly be relied upon to reduce the sanction from the two-year period," the tribunal said.
"Unfortunately, we see this case as involving behaviour by the athlete as very careless at best and reckless at worst."
Coleman won gold in the 100m and 4x100m relay in Doha last year, having claimed silver in each event in London in 2017, beating Usain Bolt into third in the individual final.
He ran 9.76 seconds in Qatar in September 2019, the sixth-fastest 100m time in history and the third-fastest by an American, behind Justin Gatlin and Tyson Gay.
He set a new world record over 60m indoors in February 2018, clocking a time of 6.34 seconds in Albuquerque.