Emmett, 43, was arrested at London's Heathrow airport after arriving from Dubai, where his wife Abbie, 27, fell several stories to her death from a window in a high-rise hotel in February.
The couple were in Dubai for a 48-hour stop after their wedding and honeymoon in Cape Town, South Africa, and their planned return to Britain, the British Broadcasting Corp. reported.
Emmett had his passport returned to him by officials in the United Arab Emirates after a probe into his wife's death concluded, the British newspaper the Mirror reported.
Her death was recorded by Dubai authorities as a suicide, and police initially said they did not believe there were suspicious circumstances, the BBC said.
Emmett was the winner of 19 British Superbike events in his career.
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