It's a simple desert scene: cacti, red dirt, yawning blue sky. The brushwork is unschooled, even naive. Surrealism may be a distant influence. The painting would be of little interest, if not for the signature, cramped into the bottom right-hand corner of the picture: "Pete Doige 76," it says.

The final, cursive "e" seems to dangle, as if acknowledging the weight it's bearing. Without that letter, the name would be "Doig," and the name "Doig" is worth a lot of money.

It belongs to one of the most successful painters in the world: Peter Doig, a Scotland-born, Canada-raised superstar of the art market, whose eerie 1990 composition Swamped commanded more than $25-million (U.S.) at auction last year.

Story continues below advertisement

But Peter Doig insists he is not Pete Doige, and that he didn't paint the desert scene. That simple contention is at the heart of a bizarre legal case that is challenging the artist's control over his body of work, not to mention his biography.

In a trial set to begin Monday, he is being sued for between $5-million and $7-million by the owner of the unnamed painting, a retired Sault Ste. Marie corrections officer who claims to have bought the piece from Mr. Doig in the mid-1970s.

Robert Fletcher insists Doig and Doige are one and the same. He says he met him when the young man was serving a jail sentence for LSD possession in Thunder Bay. And Mr. Fletcher believes the painting – which he bought for $100 – could have netted him a fortune if the artist and his lawyers hadn't interfered.

When the case goes to trial in Chicago next week, Mr. Doig will be fighting to disavow a work he denies having painted – a scenario with few precedents. Even stranger, he will be resisting an effort to write a chapter of his life he denies having lived.

About five years ago, a friend of Mr. Fletcher's noticed the desert painting hanging in the retiree's home – an acrylic on linen, measuring 34 by 41.5 inches. The signature caught the friend's eye – he recognized the name, and told Mr. Fletcher the artist was famous.

Peter Doig is among that rare breed of artists who make headlines. Although his ominous, beautifully coloured pictures are esteemed by critics, it is usually his sticker prices that earn column inches. In 2007, his White Canoe went for $10-million at Sotheby's, setting a sales record for living European artists. (The figure, he later said, made him "feel sick.")

So when Mr. Fletcher looked the painter up, and recognized him, he thought he might have stumbled into a windfall. Suddenly, his long-ago encounter with Pete Doige seemed freighted with significance.

Story continues below advertisement

Mr. Fletcher says that the pair met at Thunder Bay's Lakehead University in 1975 or 1976. Their next encounter was at Thunder Bay Correctional Centre, where Mr. Fletcher worked as a corrections officer and Mr. Doige was in custody for LSD possession.

During his roughly five-month stint in jail, Mr. Doige took art classes, and painstakingly completed a desert tableau – technically impressive for an untrained painter. When he was released, Mr. Fletcher became his parole officer, and bought the painting for $100 as a favour to his charge. Mr. Fletcher also helped the young man land work through the Seafarers' Union, he says.

He thought little about the painting, it seems, until coming to believe that it had been made by Peter Doig. Now there was no question of neglecting it; with his brother's help, Mr. Fletcher arranged to sell the work through Chicago gallery owner Peter Bartlow.

It wasn't just the similar names that convinced Mr. Fletcher of his painting's lucrative provenance – other coincidences seemed to suggest that it might be a Doig. Both the man he knew in Thunder Bay and the famous artist Peter Doig had been born in Scotland in the 1950s. A little research turned up the fact that Mr. Doig occasionally used LSD as an adolescent, and once told a newspaper that he quit at 18, which would have been about his age on his release from prison in Mr. Fletcher's version of events.

The desert painting, meanwhile, hinted at commonalities with Mr. Doig's later work. It is by no means a dead ringer for his mature style – more literal, and less accomplished, obviously – but, on the other hand, it's a hauntingly empty landscape, with a pond in the foreground: a few of the artist's hallmarks.

After Mr. Fletcher and Mr. Bartlow put the work up for sale, Mr. Doig denied authorship and sent a cease-and-desist letter through his lawyers. That prompted Mr. Fletcher and Mr. Bartlow to sue for damages; the disputed authorship has rendered the painting virtually worthless, except maybe as a curio.

Story continues below advertisement

"Whatever a judge says about authenticity is irrelevant," said Amy Adler, an expert on art law at New York University. "The market will follow Doig's word."

For Mr. Doig, the stakes are more than financial. He now faces the prospect of having a painting added to his oeuvre against his will. It's such an odd scenario, and Mr. Doig's protestations are so vehement, that few observers expected the case to reach trial. But U.S. District Court Judge Gary Feinerman denied the defendant's request for summary judgment, citing a series of tantalizing facts that seem to tie Mr. Doig to the desert picture.

There is, for example, a gap in the documentary record of Mr. Doig's life that coincides with the period in which the painting was made, according to William Zieske, Mr. Fletcher's lawyer. And in January, 1976, Mr. Doig visited friends in the desert state of Arizona.

The defence says these "uncanny convergences" are nonsense. They have sworn statements from 10 people – including family, friends and former colleagues – refuting the notion that Mr. Doig was outside of Toronto for eight months between 1975 and 1977.

In court submissions, lead defence lawyer Matthew Dontzin points out that Mr. Doig has no criminal record, and no record of serving time in Thunder Bay.

There is no record of Mr. Doig enrolling at Lakehead University, either. And there is no record of Mr. Doig joining the Seafarers' Union.

Story continues below advertisement

Most importantly for their case, the defence tracked down a man who checks those boxes: the late Peter Edward Doige, who died in Alberta in 2012. His sister, Marilyn Doige Bovard, describes her brother in a way that lines up neatly with Mr. Fletcher's description of the desert scene's creator.

Mr. Doige was enrolled at Lakehead in 1976. Records confirm that he became a member of the Seafarers' Union in Thunder Bay in 1978. He had family in Arizona. And he loved to paint, his sister says.

Mr. Doige has no record of incarceration at Thunder Bay Correctional, and Mr. Zieske contends that Lakehead enrolment records prove that he could not have been jailed at the time the painting was made. But Ernie Adams, former art teacher at the jail, swore under oath that the man he watched paint the desert scene was Mr. Doige.

In a further wrinkle befitting the uncanny quality of the case, Mr. Doige bore a strong resemblance to Mr. Doig – including in the photo that Mr. Adams based his recollections on. The plaintiffs argue that the resemblance deepens the mystery of the painter's identity. This seems to suggest a possibility that neither party imagined when the case began: that Mr. Doig and Mr. Doige were shadow versions of each other, something approaching doppelgangers, leading parallel but widely divergent lives – both moving to Canada as boys, both painting, both dabbling in LSD, one thriving, one failing to thrive – and after decades spent in total ignorance of the other, improbably converging.

"The preposterous facts of this case sort of lend themselves to myth or fiction," said Prof. Adler, the art law expert. The case has a hallucinogenic quality, she added. "It's sort of Doig-like in a weird way."