“We made a presentation of evidence and advocacy to DOJ without having seen the prosecution memo,” a defense lawyer, Andrew Good, who represented Dr. Goldenheim, said in a statement. “No charge of false testimony or concealment of abuse was brought because none of that happened.” Mr. Friedman did not respond to requests seeking comment.

Mr. Brownlee, the United States attorney, later testified that he believed the misdemeanor charges against the executives were “appropriate” given the evidence. But former government officials said he was upset by the department’s decision not to support more serious charges.

A former Drug Enforcement Administration official, Joseph Rannazzisi, said Mr. Brownlee told him that the decision had left him with little choice but to settle the case because his small team of prosecutors faced being overwhelmed by Purdue Pharma’s unlimited resources.

“He told me he was outgunned,” Mr. Rannazzisi said. Mr. Brownlee, who is now in private practice, declined to comment.

At a court hearing held in 2007 to approve the settlement, a prosecutor who had worked on the case, Randy Ramseyer, said the misdemeanor pleas by the three officials would send a message to drug industry executives that they faced being held “to a higher standard.”

But drug companies continued to flood areas rife with drug abuse with more opioids. Starting in 2007, the year of the settlement, distributors of prescription drugs sent enough pain pills to West Virginia over a five-year period to supply every man, woman and child there with 433 of them, according to a report in the Charleston Gazette-Mail.