CHICAGO — A federal judge in Chicago is set to issue a verdict in a peculiar civil trial over a celebrated Scottish-born artist’s insistence that he did not paint a landscape work that was once valued at more than $10 million.

Some of Peter Doig’s paintings have sold for over $20 million, and the owner of the disputed painting, a prison official from Canada, sued in U.S. court for millions in damages after its projected sales price tanked following the 57-year-old Doig’s disavowal of it.

The owner, Robert Fletcher, of Ontario, Canada, maintains that the painting of a desert landscape with giant red rocks and a receding pond, which he paid $100 for in the ’70s, is by Doig. If it’s not, one filing by Fletcher’s lawyers says, “it is essentially worthless.”

Authenticity disputes typically arise long after an artist dies, not, as in this case, when the artist is still living and flatly denies a work is his. The oddity of such a dispute making it all the way to trial has drawn the interest of the wider art world.

After a week of testimony at the bench trial, U.S. District Judge Gary Feinerman said he would announce his verdict Tuesday. The suit was filed in Chicago because one auctioneer who had expressed interest in selling the painting is based in the city.

Robert Fletcher contends he bought the painting from Doig around 1976 — when he says Doig was serving time on an LSD possession charge in Canada’s Thunder Bay Correctional Center, where Fletcher was employed. It was long after he bought it that a friend saw it at Fletcher’s home and said it appeared to be by an internationally acclaimed artist.

Doig, who now lives in Trinidad, said he didn’t begin using the type of linen canvas the work in question is painted on until late 1979. He also told the court that he was never been imprisoned in Ontario or anywhere else in Canada.

Such a dispute would seem easily resolved with documentation, though Canadian prison and school records from that era were sometimes imprecise, lawyers in the case have said.

A key witness for Doig was a Canadian woman who told the court the painting is actually by her now-deceased brother, whose name was Peter Doige, with an “e,” like the signature on the disputed work.

Meanwhile, Fletcher’s lawyers suggest Doig is disavowing the painting because, if Fletcher is right, it would link him to prison in his youth.