While reading the Wikipedia entry for Baha Men's 2000 hit song Who Let the Dogs Out, unemployed artist Ben Sisto found an incomplete citation. He decided he'd complete it and fill in the blank himself.

It sounds simple enough, but from there Sisto fell down a rabbit hole of calypso, competing claims and copyright law, all in the effort to answer the age-old question: Who let the dogs out?

The story of Sisto's hunt and the answers he found are the subject of Who Let the Dogs Out, a documentary that made its Canadian premiere last month at the Calgary Underground Film Festival, and plays at the Hot Docs Film Festival in Toronto on May 2.

There was nothing particular about the song that attracted Sisto, a New Yorker originally from Providence, Rhode Island. He was just bored and saw a challenge, he told Day 6 host Brent Bambury.

Ben Sisto traced back the origins of the song 'Who Let the Dogs Out.' His story is the subject of a documentary by the same name. (Hodgee Films)

The documentary opens with a clip of Sisto calling Lita Rosario, a lawyer for a record company that fought Baha Men's representation for credit. In it, she accuses him of digging up old dirt.

"I understand she was defensive. This is a case that's almost 20 years-old," Sisto said, adding that if his fact-finding gets someone into trouble, "it's not my intent but it's also not my problem."

"[The Wikipedia article] said the song was heard on a float in Trinidad by a guy named Keith. But Keith's last name was not present. And I thought I should figure out who that was and fix the wiki. That's kind of all I wanted to do," Sisto said.

But once he'd tracked down Keith Wainwright, a hairstylist who'd heard the song and passed on a recording of it to music producer Jonathan King, that led him to someone else. And so on. And so on.

"There were stretches of like six months where nobody would write me back, then all of a sudden somebody would and it would propel the story forward. I kept getting sucked back into it like it was the mob or something," said Sisto.

Eventually, Sisto turned his research into a university-style lecture show. When Alberta-born director Brent Hodge saw it he was hooked, despite finding the song "extremely annoying."

Brent Hodge is the Canadian-born director of 'Who Let the Dogs Out,' by Hodgee Films. (Hodgee Films)

"I found myself really thinking about who actually let the dogs out and why this question has probably been asked 100 times in my life and why we never really got to the bottom of that," Hodge said.

His Vancouver-based film company, Hodgee Films, teamed up with Sisto to make a movie.

The documentary took about six months to make and premiered at the South by Southwest festival in Austin, Texas, in March. In the style of Al Gore's climate change documentary An Inconvenient Truth, it centres around Sisto doing his talk in front of an audience.

"I always claim that I'm the Baha Men in this situation, where I just took a song that was already done and re-did it in my own way and put it out as the movie and took all the credit," Hodge said.

The Baha Men perform at SAFECO Field in Seattle, Wash., during the pre-game show of the Seattle Mariners vs. the Kansas City Royals on Sept. 12, 2000. (Ben VanHouten/Associated Press)

Baha Men released Who Let the Dogs Out in 2000 and it quickly became popular at sporting events. The song was a cover of Doggie by Anslem Douglas.

Sisto says the credit for the cover's success should go to music producer Steve Greenberg.

"He was really the one who saw this song called Doggie from Trinidad and Tobago and realized it had crossover potential, and he was the one [who] infused it with the thickness of Miami Bass and the crossover sensibilities and the rap parts," Sisto said.

"So when you hear Who Let the Dogs Out, by Baha Men – who by the way didn't even want to record it themselves – you're hearing Steve Greenberg's vision."

Anslem Douglas performs at a Carnival event in Port-of-Spain, Trinidad in February 1998. The soca musician wrote the original song, "Who Let the Dogs Out?" (Shirley Bahadur/Associated Press)

But did Douglas write the song that Baha Men made famous? That's where things get tricky.

Douglas says he did, but as the documentary shows, Sisto says there are at least six people who say they wrote Who Let the Dogs Out, and twice as many who say they "gave it a little extra flavour."

The most contentious element seems to be the song's famous hook: "Who let the dogs out?"

In the documentary, Sisto traces back the song's history, introducing earlier and earlier recordings that feature the hook or something very similar, such as "Who let them dogs loose."

He also introduces the people behind those songs and the legal battles they fought to get credit.

"For a lot of them, it's the closest they got to fame. I think when they're that far from something that makes this big of an impression, that makes this much money, it's got to be tough to live that close to this sizzling steak but never take a bite," Sisto said.

A still from Hodgee Films' 'Who Let the Dogs Out,' shows a timeline tracing back the recorded history of the hook: "Who let the dogs out?" (Hodgee Films)

In the end, Sisto traced the first recorded version of the hook being used in a song back to a 1992 demo by Miami Boom Productions. That demo predates several other uses in recorded music, including Douglas' Doggie.

But the dogs don't stop there. It appears that before anyone used it in pop music, the phrase, "Who let the dogs out?" was a rallying cry for high school sports teams, barked throughout the late '80s and early '90s.

The earliest proof Sisto could find of the chant is a video of a sporting event from Reagan High School in Austin, Texas, recorded in 1986. It goes: "Who let those dogs out? Who? Who? Who? Who? Who?"

"In speaking with the players from that team, they've actually told me that it probably began 1984, maybe 1983, and there are a few rumours that it could have started with a little league team just prior to that," Sisto said.

For now, Sisto says his search is over. "If Who Let the Dogs Out goes back before the time I was born [1980], then someone else can look into it."

"You get to this point where you're like: 'Who let the dogs out? Who actually did this?' And then you're like: 'What if they all did it?'" Hodge mused.

"I don't think anyone's a charlatan. I don't think anyone's trying to cheat anybody out of anything. I think there is something that you hear and it impacts you and maybe it goes into your art. That creates more art and that's kind of the point of art," Hodge said.

To hear more from Ben Sisto and to hear some of the tunes involved, download our podcast or click 'Listen' at the top of this page.