It seemed like a straightforward question.

'For years we’ve heard rumors that Justin Trudeau, the former prime minister of Canada, could be your half-brother. What do you think about it?'

Alina Fernandez, the 70-year-old daughter of Fidel Castro, didn't laugh. She didn't say no. Instead, after a slightly awkward pause, she gave a remarkably enigmatic answer.

'The only thing I can tell you is that his mother used to visit the country [Cuba] very often...'

Then she smiled. Does she perhaps know something the rest of us don't?

Fernandez's peculiar response on NewsNation's Katie Pavlich Tonight program this week has reignited online speculation that Justin could indeed be the illegitimate son of the late communist dictator.

The idea was first mooted a decade ago in the immediate aftermath of Castro's death.

However, back then, it was quashed following concerted denials by the governments of both Canada and Cuba. The state machinery in Ottawa and Havana was deployed to crush the rumors. It was, officials said, merely a conspiracy theory concocted in the informational Wild West of the internet.

However, Fernandez's comments, at the very least, have made the evidence worthy of another look.

What lawyers would call the prima facie, or most obvious, case for a link between Castro and Justin is... their faces. 

Compare Justin to a young, pre-beard Castro and the resemblance is instantly noticeable. The long straight noses, the shape of their chins, and their eyes, and the smiles, too, are similar. Note, too, Justin's thick head of dark hair. By middle age, his father Pierre's hairline had already beaten a long retreat.

Then there is the long, and what many see as bizarre, relationship between the Trudeau and Castro families, which began during the Cold War.

In 1976, Pierre Trudeau, as Canadian prime minister, became the first NATO leader to visit Cuba since the Castro revolution. 'Viva Castro!' he exclaimed publicly, leaving the US government baffled.

Photographs showed Justin's mother, Margaret Trudeau, handing his baby brother to Castro at Havana airport, with both of them looking adoringly at the infant. Later, the baby would frequently be misidentified as Justin.

A bromance between Castro and Pierre continued for over two decades. When Pierre died in 2000, Castro, regarded as a pariah by the entire rest of the West, flew to Montreal to be an honorary pallbearer.

In an extraordinarily emotional scene at the funeral, he bear-hugged Justin, then aged 28, before firmly gripping him by both arms and staring at him.

Justin made three personal trips with his family to Cuba and then, in November 2016, his first official visit as Prime Minister. The ailing Castro, aged 90, was too sick to receive him. Ten days later, he died.

Justin then issued a statement that outraged and perplexed the Western world as he declared his 'deep sorrow' over the death of the brutal dictator's death.

'Mr Castro' was, according to the Canadian, a 'legendary revolutionary and orator' who 'served his people.'

'I know my father was very proud to call him a friend and I had the opportunity to meet Fidel when my father passed away,' he said.

'It was also a real honor to meet his three sons and his brother, President Raul Castro, during my recent visit to Cuba. We join the people of Cuba today in mourning the loss of this remarkable leader.'

There was no mention of those who suffered under the Castro regime.

Marco Rubio, who is Cuban-American, said at the time: 'Is this a real statement or parody? Because if this is a real statement from the PM of Canada, it is shameful and embarrassing.'

Senator Ted Cruz of Texas, also Cuban-American, accused Justin of 'slobbering adulation' for Castro.

The statement led to ridicule and other satirical 'Trudeau Eulogies' on Twitter.

One read: 'Mr Stalin will be fondly remembered for increasing tourism to the otherwise unwelcoming Siberia.'

It also led many to wonder if there could be another reason for Justin's blind praise for a brutal dictator.

The rumor mill started up again in 2018 when Castro's eldest son Fidelito, a 68-year-old nuclear physicist who strongly resembled him, died by suicide.

Initial unconfirmed reports suggested he had left a note saying he was Justin's half-brother. But the claim of a note was never substantiated, and the link was denied by the Canadian government.

Six years later, Donald Trump reinvigorated the claim in his book Save America.

'His [Justin's] mother was beautiful and wild,' Trump wrote. 'In the 1970s, she would go "clubbing" with the Rolling Stones, but she was also somehow associated with Fidel Castro. She said he was "the sexiest man I've ever met," and a lot of people say that Justin is his son. He swears that he isn't, but how the hell would he know!

"Castro had good hair, the "father" didn't. Justin has good hair, and has become a Communist just like Castro."

Trump went on to suggest that there was something genetic about Justin's leftist political path.

'He's turned very liberal, actually they say he's the son of Fidel Castro, and could be,' Trump told a podcast at the time. 'Anything's possible in this world, you know?'

Whatever the reason Trump made his claims about Justin's mother, they do get to the heart of the matter.

Margaret was aged just 22, and a self-described 'hippy flower child' who had been traveling around Morocco, when she met and secretly married the urbane Pierre, who was 51 and had already been prime minister for three years.

For Margaret, it was a bewildering transition and one she did not adapt to well.

She fought a long battle with undiagnosed bipolar disorder and came to see her life as first lady as a 'prison,' accusing Pierre of putting her in a 'birdcage.'

She once described her husband as 'old, with old skin and old toes.'

Before giving a speech at a state dinner in Venezuela, she ate peyote, the hallucinogenic cactus, and embarrassment ensued.

Her life was plastered across tabloid newspapers as she was spotted hanging out with Andy Warhol at Studio 54, cozying up to actor Ryan O'Neal and tennis star Bjorn Borg, and partying and smoking marijuana with the Rolling Stones.

The Trudeaus split in 1977 and she later admitted affairs during their relationship, although not with the band.

'It's really embarrassing. It just isn't true, Mick Jagger said. 'She just came for a two-night concert. She just wanted to have a good time. She was a 'very sick girl in search of something,' Jagger added. 'She found it, but not with me. I wouldn't go near her with a barge pole.'

Given her remarkable free-spirited life, it would not be out of the realm of possibility that Margaret, now aged 77, might have decided to have a relationship with Castro as a young woman.

The crucial question is how that could have happened at the right time, given that her only documented trip to Cuba was the historic official state visit with Pierre in 1976.

She had married Pierre on March 4, 1971, and Justin, the eldest of their children, was born on Christmas Day 1971.

Experts have established that Justin must have been conceived between March 16 and April 22, 1971.

Intriguingly, Pierre and Margaret took what was described at the time as a 'second honeymoon' in the Caribbean between April 8 and 18, 1971.

There is no clear evidence their stops included Cuba but their trip was shrouded in secrecy and it leaves open the possibility.

On April 10, 1971 the Ottawa Journal, citing a report by Reuters, said the couple had arrived in Barbados by plane at midnight local time two days earlier

It said: 'They were met at the airport by a small group of officials and left the airport for an undisclosed location.'

On April 13, 1971 the UPI news agency reported that 'Prime Minister Trudeau and his wife left here Monday on a chartered plane for a quick side trip to an unidentified nearby island.'

It remains unclear what that island was. 

By April 16, according to Reuters, they were in Trinidad and Tobago, but separately.

Trudeau was in Tobago meeting the prime minster, Dr Eric Williams, leaving his wife in Trinidad.

According to that report they had also visited the Grenadines, and were due to return to Canada on April 18.

Robert Wright, a Canadian historian who wrote the book Three Nights in Havana about the relationship between the Castro and Trudeau families, has described the idea of Castro being Justin's father as 'preposterous.'  

Also counting against the suggestion, Margaret herself has never given credence to the claim despite revealing her wild life in a series of tell-all memoirs.

It is worth noting that the young Pierre, before he lost his hair, also bore a passing resemblance to Castro.

Still, there are those who continue to believe there is something to the rumors.

'Do you plan to call him [Justin] and maybe find out?' Fernandez, Castro's daughter, was asked.

'No, no,' she said. 'If he wants, he’s welcome, but I won’t. I think he keeps that to himself, and you have to respect that.'