A member of the family that owns the manufacturer of OxyContin repeatedly gave testimony in a lawsuit that conflicts with details in a report by federal prosecutors, newly disclosed court papers indicate.

Dr. Richard Sackler, who was once president of the company, Purdue Pharma, and is the son of one of its founders, said under oath during a pretrial deposition that he first learned from a Maine newspaper article in 2000 that OxyContin, a powerful opioid painkiller, was being abused.

His statement contradicts evidence in a confidential Justice Department report from 2006 that came to light last year. In the report, prosecutors pointed to a 1999 email indicating that Mr. Sackler was told then that in internet chat rooms, drug abusers were discussing crushing and snorting OxyContin. A Purdue Pharma spokesman stood by the accuracy of Mr. Sackler’s testimony and added that he was unable to comment on the claims in the Justice Department report because the company had not seen it.

The deposition, in a lawsuit filed by the state of Kentucky, was given in 2015 and has been sealed since. On Thursday, two news organizations, STAT and ProPublica, published the transcript of the deposition. Since the case’s settlement in 2015, Purdue Pharma has been fighting to keep the deposition secret.