Marcell Jacobs, Italy's shock 100m Olympic champion, has insisted that he has never taken performance-enhancing drugs and that his remarkable success last summer was down simply to "extreme hard work".
The 27-year-old former long jumper caused one of the biggest upsets in Olympic history in August when he streaked to victory in Tokyo, despite having only broken the 10-second barrier for the first time three months previously.
His win prompted scepticism from athletics observers, who doubted any sprinter could show that kind of dramatic improvement without the use of illegal substances.
Those suspicions escalated when he abruptly pulled out of the rest of the athletics season following the 4x100m sprint relay final in Japan, where he added a second gold medal to his individual honour. But, in his first major foreign newspaper interview since claiming Usain Bolt's sprint crown, Jacobs has mounted a robust defence of his record to The Telegraph.
Asked directly if he has ever taken any illegal substance, he said: "Absolutely not, and I would not." He continued: "People think they can say whatever they want about you without understanding that sometimes what they say can be hurtful.
"The negative pieces hurt me a bit because what they did was put doubt over my victories. My victories represent extreme hard work."
Jacobs, who said his decision to end his season prematurely was simply due to exhaustion after his efforts at the Olympics, also reiterated that he ended his relationship with his former adviser, Giacomo Spazzini, as soon as he discovered the nutritionist was implicated in a police investigation into the distribution of anabolic steroids in March 2021.
Spazzini has since been cleared of any wrongdoing by an Italian court, with Jacobs - currently training on Tenerife as he prepares for the start of the indoor season - claiming that the former bodybuilder had been the victim of "mud-slinging".
"I would never do anything as an athlete competing for my country that would bring disrepute on me as a man or on my nation," he added.
A few hundred miles off the coast of west Africa lie the answers to the mystery of the missing Olympic sprint champion.
It is nearing the end of Marcell Jacobs' weekly rest day at his training camp in Tenerife and he has just returned from a quad-bike trip up Mount Teide, the volcano whose peak is the highest point in the Canary Islands - the perfect excursion for a thrill-seeker who thrives on the biggest, fastest and flashiest.
For more than five months, there has been little word from the former long jumper who stunned the world when he unexpectedly claimed Usain Bolt's Olympic 100 metres crown. In the eyes of many outside of Italy, he seemed to disappear, oddly opting not to cash in on his overnight fame by dropping out of scheduled Diamond League appearances and immediately ending his season in August after adding 4x100m gold to his Tokyo haul.
In part, Jacobs's silence comes from a sense of anger over what he perceives as unjust treatment for winning Olympic gold, which ranks as one of the all-time unlikely triumphs in the Games' blue riband event.
While Jacobs won the European indoor 60m title last March, he had specialised as a long jumper for much of his career and only broke 10 seconds over 100m for the first time in his life in May. Three months later he clocked a European record 9.80sec to triumph in Tokyo.
History has not always looked kindly on athletes making huge strides in short periods of time, and observers were quick to cast judgement on the first Italian man ever to make an Olympic 100m final, let alone win it.
So, an obvious question: has Jacobs ever taken any illegal substances? "Absolutely not," he replies, simply. "And I would not."
And how did he react to questions around his decision to stop running immediately after the Olympics? "I understand that people were surprised, but that's because for most people my name came into their homes at the Olympics," he says.
"For the average viewer, they saw me win at the Olympics and had no idea what my season had been like before that. My season started in February and it was intense.
"The whole Olympic period was exhausting, not just for my body, but also my mind. I needed to regenerate my mind and body. I never lost my desire to compete."
Jacobs' retreat from public life did not mean that the trail controversy ended, of course. His elevation had been so fast that he was the only sprinter in that 100m final not included in the highest tier of the Athletics Integrity Unit's anti-doping testing pool. It then emerged that his one-time nutritional advisor, Giacomo Spazzini, was implicated in a police investigation called 'Operation Muscle Bound' into the illegal distribution of anabolic steroids.
The day after Jacobs won Olympic 100m gold, Spazzini had posted about their relationship on social media: "Since we started out together, at the same time as a mental coach, everything has changed. His body has begun to react to the correct nutrition… the method that I designed years ago and which we are constantly evolving. I am really proud to have been part of this transformation."
It was a troubling association for Jacobs, but today the world's fastest man is feeling bullish about what he describes as "mud-slinging" against him. Spazzini has this month been exonerated of all charges against him in a Milan court, which concluded they were without foundation.
It also described Spazzini as an injured party in the connected case of Antonio Armiento, a former colleague who struck a plea bargain after falsely declaring himself to be a medical nutritionist and prescribing growth hormones without proper authorisation. Jacobs was never part of the investigation.
"The whole situation wasn't easy," says Jacobs, 27, in his first major interview with a foreign newspaper since the Olympics. "When I found out [about the investigation], I was the first person to remove myself from the situation and cut off contact with Spazzini last March .
"But there was a lot of mud slung about him as a person and a professional. A lot of the accusations were wrong. I've always tried, through all my professional career, to put all of myself into everything I do and win cleanly.
"Everywhere I go, I represent Italy. I carry the flag, the nation and my identity with me. So it's a question of respect for the flag on my uniform when I compete. I would never do anything as an athlete competing for my country that would bring disrepute on me as a man or on my nation."
He adds that he has not contacted Spazzini since the court verdict, but that "everyone deserves a second chance".
Jacobs has his own links with the Italian authorities in his honorary role as a police officer in a country where athletes are regularly employed by enforcement agencies and given financial support to train. He often races in a maroon 'Polizia' vest and is due a promotion after his Olympic success.
Born in Texas to an American father, he moved to his mother's Italian homeland before his first birthday and spoke no English when growing up. His grasp of the language is improving but remains rudimentary, and he prefers to conduct the interview through a translator, needlessly apologising for not being able to converse fully in English.
He describes life since the Olympics as "like being under a magnifying glass", and the only subject off limits is that of his son from a former relationship - he also has two young children with his fiancé Nicole Daza - whose mother has recently publicly criticised Jacobs for his absence in the boy's life.
"Life is a little bit less easy now," says Jacobs. "People think they can say whatever they want about you without understanding that sometimes what they say can be hurtful.
"The negative pieces hurt me a bit because what they did was put doubt over my victories. My victories represent extreme hard work - hard work that nobody saw, hard work that was blood, sweat, tears and injuries."
It is undeniable that - for all his reticence in engaging in public for the last six months - his celebrity has exploded in his home country.
A quick scroll through his social media feeds show the benefits of being a newly-minted Olympic champion: a guest appearance at the Italian Grand Prix where he met his idol Lewis Hamilton, a meeting with fashion designer Giorgio Armani in Dubai, a startling cover shoot for Italian Vanity Fair where his tattooed, hairless body and rippling muscles were covered only by a national flag carefully draped over his shoulder to protect his modesty while a crown sat atop his head. In September, he asked Daza, a self-proclaimed 'fashion girl', to marry him.
Such is the public interest in his newfound status as the world's fastest man that he has brought in an international management agency, with ex-Italian prime minister Silvio Berlusconi's former spokesman Marco Ventura as a media consultant, while one of his recent Instagram posts shows him reclining in a private jet.
Jacobs insists, however, that perceptions of his lifestyle do not quite match reality. "It seems like my life has changed a lot but it hasn't really," he says. "I'm still the exact same person who wakes up in the morning full of energy and desire to train. That's what I still do every day. I still train at the same athletics facility I always have done.
"I turn up with my speakers and even though I'm Olympic champion, if someone is already there playing their music, I can't take it off to play mine. It's still the same old life and same old person."
Even the jet? "It was a gift - I had been invited to an event and because I can't miss a training session, the only way to get me to the event was on a private plane," he says. "It was a first for me, but I'm actually a little bit afraid of flying."
For most of his career Jacobs was an aspiring long jumper, who repeatedly fell short of medal standard at international level. Indeed, his social media name remains "crazy long jumper", although he says he has recently tried to change the second part without success. The "crazy", he says with a smile, will stay for life.
Responding to those who wonder how it is possible to rise so rapidly in the sprinting ranks, he points to America's former 400m runner Fred Kerley, who claimed Olympic 100m silver behind Jacobs in 9.84sec despite a personal best of 10.49sec before last season.
"This happens when you come from a different discipline," says Jacobs. "The fact that you haven't done the 100m for your whole life allows for more improvement and faster improvement."
That will not satisfy all the sceptics, of course, and his performances - when he finally does return to the track - will be pored over in minute detail.
Not that Jacobs seems to care: he cuts an intensely relaxed figure throughout our conversation, even resisting the opportunity to poke fun at the fact that the only European sprinter to have failed a drugs test taken at the Tokyo Games was Great Britain's GB's 4x100m lead-off runner Chijindu Ujah, although he does observe it is "ironic" that most of his most vocal critics were based in the United Kingdom.
In the immediate aftermath of his Olympic triumph, Jacobs said the factors behind his sudden elevation to the top of the sprinting world were as much in his head as they were physical, explaining that his mental coach Nicoletta Romanazzi had encouraged him to loosen tension by establishing a relationship with his estranged father. He now adds that Romanazzi's influence saw him make "a fundamental switch from concentrating on the others in a race to concentrating on myself".
The issue now is that everyone else will focus on him; the man with a target on his back. He returns to action for the first time since his Tokyo victories - since memorialised on his body in the form of a tattoo of the Olympic rings - at an indoor meet in Berlin on February 5, before taking on 60m world champion Christian Coleman - who was absent from the Olympics due to doping violations - at March's World Indoor Championships.
The intention is to race over 200m a few times in the summer, but he will not step up in distance at a major championship until the 2024 Paris Games.
The year's focus remains replicating his Olympic 100m success over the same distance at July's World Championships, although he is adamant his two Tokyo wins should not be written off as flukes, irrespective of how he fares.
"When you win two gold medals, it's not an accident," he says. "Gold medals stand for lots of work that went into winning them.
"This summer, everyone will be gunning for me and I will be the one to beat. But I feel just as committed and just as hungry. The big difference is that now I've won the medals, it can also be fun."
As the interview is wrapping up, Jacobs, perhaps in a bid to endear himself to a British audience, says he would like to convey that his two sporting heroes are in fact British: Anthony Joshua, because Jacobs loves boxing and is fascinated by the former heavyweight world champion's journey, and Hamilton, the seven-time Formula One world champion.
"When I met Hamilton at Monza I was shaking like a leaf," he says. "I see parts of myself in him and I'm inspired by him. I am mixed-race like him, I like his look and style, and I like that Hamilton enjoys himself. He said I should stick diamonds on my gold medals."
Hamilton's sometimes brash personality has long divided opinion, but he retains a knack of winning regardless, so you can understand why Jacobs might consider him a role model.
In the mean time, the world waits to discover whether Tokyo was a startling one-off, or the first act in a stunning career.