The father of a four-year-old boy says he's relieved his son has been returned, after a Canada-wide warrant was issued for the boy's mother who disappeared with the child weeks ago in Europe.

Elizabeth De Swart, 37, had been ordered by a judge to safely return her four-year-old son (whom CBC News has chosen not to name, as he is a minor) to his father Oscar Maillard in Spain.

On July 6, the mother and child flew from Calgary to Frankfurt, then vanished.

Maillard said Spanish authorities issued a warrant for De Swart's arrest, and after she disappeared he started receiving daily emails saying his son was safe — but no further details.

Emails traced to Netherlands

He traced the IP address the emails were coming from and drove 1,700 kilometres from Spain to the Netherlands to start searching for his son, where he connected with Dutch police.

Last week, police drove him to De Swart's grandmother's home in Amsterdam, where they spotted De Swart — and their son.

"I see Liz walk out … it was just a complete fluke, like we didn't, I didn't know they were there," he said on Saturday. "I burst out in tears when I saw her walk out of the apartment. I just, I knew it was over. I knew I was getting my son back."

He said the three of them rode back in the car to the police station without the adults exchanging a single word.

Father and son spent one night in a hotel, before returning to their home in Alicante, Spain, on Saturday.

CBC News has reached out to De Swart's lawyers multiple times for comment and received no response. CBC has also reached out to a member of De Swart's family, who declined comment as De Swart is currently pursuing an appeal, and instead pointed media to an online fundraising page for her.

Child taken without father's knowledge in May

A June 25 ruling from the Court of Queen's Bench of Alberta had ordered De Swart to provide for the safe return of her and Maillard's child to Spain.

The document states that Maillard, a French and Canadian citizen, and De Swart, a Dutch and Canadian citizen, moved late last year from Calgary to France with their son, who was born in Canada.

In March 2019, the couple moved to Spain and enrolled their son in school. Maillard was working in Africa on rotation, so he was frequently travelling between the two continents. He had been back at work in Africa for about a week in mid-May when he called De Swart and couldn't reach her.

Maillard then discovered that the child hadn't been to school in Spain since May 2, and that De Swart had fled with the child to Calgary without telling him. At that point, he filed a Hague application to get his son back.

The Hague Convention is an international treaty that deals with issues of child custody and access that cross borders.

Maillard said the child is happy and safe at home in Spain with family and friends, and that he hopes to say more about the legal situation with the boy's mother in the coming days.

Mom fundraising for legal fees

An online fundraiser started by De Swart's sister has raised more than $14,000 for her legal fees.

"I am overwhelmingly thankful for everyone's love and support. Once the dust settles everyone will have a chance to hear 'the other side' of the story. For now we must continue to brave, patient and kind," read an update to the fundraising page purportedly written by De Swart.

A Canada-wide warrant has been issued for Elizabeth De Swart, of Calgary, who is accused of abducting her son by failing to return him to his father in Spain. CBC News has blurred the child's face to protect his identity. (GoFundMe)

De Swart also made allegations that Maillard was abusive and that the couple had been separated before she left Spain with the child, but those were rejected in the justice's ruling.

"This has felt like an unbelievable drama that is unfolding but it is, in fact, not a unique story. Time and time again systems and people fail one another," a post to the fundraising page reads.

'I can't be more thankful,' says father

Maillard said he's going to spend a few weeks reconnecting with his son before re-enrolling him in daycare.

"I have to just go spend every single minute with him right now … we're just going to relax and just catch up on all these months we haven't been able to spend together," he said.

Maillard thanked the various international justice systems for their cooperation and speed in the case.

"I'm a male … especially when it comes to custody and these kinds of family matters generally we're the ones that don't really, it definitely doesn't work in our favours half the time. But here, the facts were so strong and the justice system was so good and it was just. They did their job. And I can't be more thankful," he said.