The publisher of top-selling Haitian Canadian writer Thélyson Orélien, who was removed from France’s most prestigious literary prize list last month, has confirmed the author used artificial intelligence to help write his novel C’était ça ou mourir (It Was Either That or Die).

Orélien has denied allegations that he used AI on his breakthrough novel and, last week, Canadian publisher Les Éditions du Boréal said it was standing by the 38-year-old writer.

But on Wednesday, Boréal said it had conducted a further investigation into the allegations.

“New information, confirmed over the past few days, indicates that artificial intelligence was used in the writing process” of the novel, a statement from Boréal said.

The publisher announced it was “ending its professional relationship” with Orélien.

Boréal said it did not know the extent of AI’s use in the writing process “and we will likely never have a definitive answer”.

It said it gathered all the working versions of the novel and hired an outside party to analyse various drafts.

“The results obtained this week revealed traces of AI tags in the metadata of certain documents,” Boréal said.

Before conducting this analysis, the publisher said it had tried to work with Orélien to gather the evidence necessary to prove his innocence.

That effort was inconclusive, and Orélien “subsequently announced that he would not provide any further information,” the publisher said.

The novel about migration had been scheduled for translation in more than 20 countries.

The book was shrouded in suspicion and withdrawn from the list for France’s book prize the Prix Goncourt, after tests with AI detector Pangram indicated a 100% probability it contained computer-generated text.

In a statement to Agence France-Presse earlier this month, Orélien called the allegations “slander and heresy”.

“Here and there I did use tools for research, particularly for foreign idioms,” he said in a statement sent exclusively to AFP.

“But not a single sentence in this book was created by a machine, nor the meaning or the structure of a story that comes from my gut.”

He stood firm on Wednesday, telling the French newspaper Libération he used AI “in the creative process” for “historical research”.

“I’ve explained everything to those close to me, but at the moment I don’t think my words count for anything,” he said, adding that what he is now experiencing has “gone way too far”.

Orélien said he started writing the book in late 2017 “on the corner of a table” and completed a first draft in 2019 of more than 300 pages, several years before the advent of AI services such as ChatGPT.

The author fled his native Haiti after a 2010 earthquake that struck the Caribbean island, already ravaged by poverty and unrest.

In response to separate allegations of plagiarism, Orélien admitted to making “unacceptable mistakes” in the past in his writing, without mentioning specifics.

“I was just over 20, I was probably a little too impatient, without really understanding how much I still had to learn. I wanted to write, I was reading a lot,” he wrote.

“But admiring someone does not give you the right to take, to claim as mine texts that are not my own.”