A North Carolina federal judge has eviscerated a former federal prosecutor in a public reprimand for his use of artificial intelligence to draft a response brief that was riddled with hallucinations, calling out the prosecutor's "lack of candor" and saying he "disgraced not only himself, but also the entire office he formerly served."

U.S. Magistrate Judge Robert T. Numbers II pulled no punches in an 18-page order Monday reprimanding former Assistant U.S. Attorney Rudy E. Renfer, who worked in the U.S. Attorney's Office for the Eastern District of North Carolina for 17 years before he was fired in March. Judge Numbers said sanctions against the veteran prosecutor are necessary to prevent further "abuse of the judicial process" and signal that false citations "will not be tolerated by this court."

According to his order, the AI debacle cost Renfer his job and has prompted an investigation by the U.S. Department of Justice's Office of Professional Responsibility.

"Renfer's professional reputation, both locally and nationally, is in tatters," Judge Numbers wrote. "In this court, his name will be synonymous with a failure to uphold the basic duties of competence and candor expected of every attorney."

The judge held back on monetary penalties, noting the loss of Renfer's career "imposes a financial burden well beyond the types of fines courts typically impose in connection with AI-related misdeeds."

The incident occurred while Renfer was representing the U.S. Department of Defense and its top brass in a healthcare benefits lawsuit brought by veteran and licensed attorney Derence V. Fivehouse. Fivehouse is challenging a policy change that excludes certain Tricare For Life beneficiaries from coverage of GLP-1 medications. He's a retired U.S. Air Force colonel and former civilian attorney with the military branch.

In December, Fivehouse alerted the court that the DOD's response to his motion to supplement the administrative record contained fabricated quotations and misstated case holdings, prompting Judge Numbers to seek an explanation from Renfer.

Renfer claimed it was a clerical error, saying in a written response that he inadvertently filed an unfinalized draft version of the brief with the court. Judge Numbers subsequently hauled him into court for a show cause hearing March 10, at which time Renfer apologized and offered his resignation from the U.S. attorney's office.

According to Monday's order, Renfer did not mention his use of AI in either the initial written response to the court or the statement he read on the stand during the show cause hearing.

It was only when Judge Numbers pressed him later in the hearing about the specific instances of hallucinations in his brief that Renfer reportedly owned up to having used AI to draft the response. He claimed he had to "catch up" after realizing he'd accidentally overwritten the draft, the order states.

U.S. Attorney Ellis Boyle of the U.S. Attorney's Office for the Eastern District of North Carolina attended the hearing and apologized on behalf of his office. Boyle claimed to have no knowledge of Renfer's use of AI. Renfer was reportedly fired the following day.

Judge Numbers said there is "no question" as to the bogus quotes and misstatements contained in Renfer's brief, which he said justify sanctions under his inherent authority.

He rejected Renfer's claim that the mistakes were unintentional merely because the former prosecutor meant to double-check the accuracy of his response but did not. According to the judge, "it is a basic principle of law that an actor is responsible for the natural and foreseeable consequences of his acts."

"It is, at this time, foreseeable that generative AI tools will provide fabricated legal authority when asked to engage in legal analysis," Judge Numbers wrote. "Renfer cannot avoid the consequences of his failure to account for that reality."

The judge also did not find Renfer's testimony about his reason for using AI to be credible. Renfer claimed he "panicked" after realizing he had accidentally saved over the draft response brief and needed to catch up quickly. He allegedly realized the problem Dec. 22, but the response wasn't due until eight days later on Dec. 30, Judge Numbers said.

"Given the time Renfer had left to respond, there was no need for panic, no need to use an AI tool to catch up, and no need to file the response brief without proper vetting on December 23, 2025," he said.

The judge accused Renfer of burdening the court and wasting Fivehouse's time, saying his use of fake citations "cast a shadow of invalidity on the judicial process."

Judge Numbers also said Renfer's "lack of candor" by failing to own up to the mistake sooner weighed in favor of sanctions. He noted other courts "have shown grace to attorneys who promptly admit their mistake."

But, he said, "courts are less forgiving of attorneys who are unwilling or unable to do so."

The judge went on to call Renfer's actions "particularly odious" given his "position of immense trust and power" within the U.S. attorney's office.

In closing, Judge Numbers urged counsel to exercise caution if they choose to use AI tools in their work, noting the accuracy of the information should always be verified. A lawyer who fails to do so "will be held accountable," he said.

"Attorneys should ask themselves whether the time and effort they will save by using generative AI to draft a legal document is worth the damage their career and professional reputation will suffer if they do not ensure the document's accuracy," Judge Numbers wrote.

A spokesperson for the U.S. Attorney's Office for the Eastern District of North Carolina confirmed Renfer was terminated on March 11, saying "we acknowledge the prudent and firm tenor of the court's order and intend to fully comply."

In a statement to Law360 on Tuesday, Fivehouse said he has the "greatest respect for the line attorneys at the Department of Justice."

"This episode is regrettable," he continued. "However, Magistrate Judge Numbers' order speaks for itself. The court conducted its own inquiry, made its own findings, and has now issued a written reprimand. That is the judicial process working as it should."

Renfer could not be reached for comment.

Fivehouse is representing himself.

The DOD is represented by Neal Fowler of the U.S. Attorney's Office for the Eastern District of North Carolina.

The case is Derence V. Fivehouse v. U.S. Department of Defense et al., case number 2:25-cv-00041, in the U.S. District Court for the Eastern District of North Carolina.

--Additional reporting by Abigail Harrison. Editing by Patrick Reagan.

Update: This article has been updated to include a response from the plaintiff and the U.S. Attorney's Office.

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