Sixto Rodriguez's music went nowhere in the U.S. -- but made him a star in countries such as South Africa. (Sony Pictures Classics)

"And now you hear the music, but the words don't sound too clear …"

"Inner City Blues" by Sixto Rodriguez

Former Baltimorean Craig Strydom has spent more than two decades searching for Sugar Man. And even though the music journalist tracked his elusive subject to a Detroit tenement in 1997, in many ways, he's still looking.

Sugar Man is the nickname for Sixto Rodriguez, a Mexican-American singer-songwriter who was living in dire poverty in the U.S. without ever knowing that his music was being used to fight apartheid halfway around the world. His compelling and improbable story of resurrection is chronicled in a film that just opened at the Charles Theatre.

Exactly how Strydom, one of two fans who refused to let their hero stay lost, located Rodriguez is a key part of "Searching for Sugar Man." It's fair to say that the sleuthing methods used by Strydom and music store owner Stephen Segerman were as desperate as they were ingenious.

"In South Africa, Rodriguez was bigger than the Beatles, bigger than the Rolling Stones, bigger than Elvis Presley," says Strydom, 48, who grew up in Cape Town. He returned to South Africa temporarily last month after 13 years in Baltimore, where he worked for the advertising firm IMRE.

Rodriguez's first album, "Cold Fact," was as popular in South Africa as the Beatles' "Abbey Road," Strydom says.

"But no one knew anything about him," he says. "There were all kinds of rumors. So I decided on a whim to see what I could find out."

Perhaps because the documentary tells a real-life story, it poses as many questions as it answers about the uneasy relationship between creativity and popular success, about the enigmatic artist, and about possible skulduggery within the music industry.

Clues to the first can possibly be gleaned from the recent flood of publicity surrounding the documentary. In the past two weeks alone, Rodriguez has been interviewed on CNN and performed on "The Late Show with David Letterman," who raved about the film. "Searching for Sugar Man" won an audience award at Sundance. The word "Oscar" is being bandied about.

Hints to the musician can be found, perhaps, by watching Rodriguez perform live. On Thursday, he will play a concert at the Sixth and I Historic Synagogue in Washington.

But it's the case of the mysterious vanishing royalty checks that most intrigues Strydom.

"The little man gets shafted, sons and moneys drafted … "

Rodriguez's "The Establishment Blues"

If Rodriguez's records went platinum in South Africa, why, Strydom wants to know, did the artist never receive even one penny of the royalties due him? Who got rich off Rodriguez's songs, while the man who wrote them was raising three little girls in homes that at times lacked a bathroom?

"No one's really gotten to the bottom of the money yet," Strydom says.

"It is a thorn in my side. When I try to call telephone numbers that are disconnected the next day, when the moneymen shut the interviews down, it was like a red flag to a bull. It's an unfinished story, and I'm thinking of taking another look at it."

In 1970, Rodriguez was poised for stardom. He wrote his own songs, and the lyrics were evocative, elliptical and politically charged.

"A lot of people thought he was going to be the next Bob Dylan," first-time director Malik Bendjelloul says over the phone. He spent four years putting together "Searching for Sugar Man" at his kitchen table on a budget of $1 million.