An anti-vaccine former kickboxing champion died at the age of 41 shortly after discharging himself from hospital and apparently suffering Covid complications, according to reports.
Frederic Sinistra passed away at his home in the town of Ciney, southern Belgium, after deciding he would personally treat what he described as a "little virus."
Forced to finally get medical help in November by his coach, Osman Yigin, the fighter known as 'The Undertaker' had uploaded pictures of himself from a hospital bed while breathing through an oxygen tube in an intensive care unit.
According to reports, the heavyweight star treated himself with oxygen at home. Later, however, his partner had to publicly announce his death via an emotional Facebook post.
"From the bottom of my heart thank you all for your support and all your wonderful tributes to my husband," she began.
"My husband was a generous man with a big heart who wanted to help others no matter what."
On the same social media platform, Sinistra explained to his 37,000 followers in what was his last post that "determination and [a] desire to be different" were the main catalysts behind a successful fight career.
"I’ve had to work twice as hard as most, I’ve fought battles no one really knows about, and of course I’ve had setbacks in my career as well as in my personal life, but it’s made me who I am where I am today," he claimed.
"For everyone else who has supported me for years, and especially for this last ordeal where I have really seen death, thank you from the bottom of my heart for your messages your support, or for your encouragement."
Before this, however, Sinistra shared a video where he was evidently struggling to breathe, and said in its caption that he had "no time to waste with lazy people".
In other posts, the staunch anti-vaxxer is said to have described Covid as a "little virus" that would not stop him amid protests against protocols imposed by governments.
On November 26, he announced that a bout planned for December 4 had been scrapped which "disgusted" him.
Despite widespread reports claiming otherwise, Sinistra's partner maintained he had not passed away due to Covid.
"He would have never accepted that his fate would be used to incite fear and market vaccines," she said in the social media post that announced his passing, while revealing that a film on his life will be released in 2022.
Sinistra won heavyweight titles at national, European and world level while amassing a respectable 39-9 record.
He was once dubbed "Belgium's strongest man", and ex-coach Fabian Pavone described him as a "force of nature with a heart of gold".
"He was a golden guy. I will never forget him," said friend Jordan Sferrazza online. "He was the strongest in Belgium in the heavyweight category."
With his passing, Sinistra joins a total of 28,149 Belgians to have lost their lives to Covid across 2.04 million total cases.