The New York Times on Friday issued a retraction for its 2018 podcast series “Caliphate,” after finding that one of its main subjects exaggerated or provided false accounts of his involvement with the Islamic State of Iraq and Syria.

After a two-month internal review, the newspaper “found that ‘Caliphate’ gave too much credence to the false or exaggerated accounts of one of its main subjects, Shehroze Chaudhry, a resident of Canada who claimed to have taken part in Islamic State executions under the name Abu Huzayafah.”

An Editor’s Note says that the investigation turned up “significant falsehoods and other discrepancies” in Chaudhry’s story.

“From the outset, ‘Caliphate’ should have had the regular participation of an editor experienced in the subject matter,” the note continues. “In addition, The Times should have pressed harder to verify Mr. Chaudhry’s claims before deciding to place so much emphasis on one individual’s account.”

The review came after Canadian authorities arrested Chaudhry in September, accusing him of perpetuating a terrorist hoax.

Times executive editor Dean Baquet said that the blame for this lies with himself and the other leaders in the newsroom.

“When The New York Times does deep, big, ambitious journalism in any format, we put it to a tremendous amount of scrutiny at the upper levels of the newsroom,” he said in a podcast interview.

“We did not do that in this case,” he added. “And I think that I or somebody else should have provided that same kind of scrutiny, because it was a big, ambitious piece of journalism. And I did not provide that kind of scrutiny, nor did my top deputies with deep experience in examining investigative reporting.”