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Medium reported severity Regulatory Action

New York federal judge sanctions two lawyers whose brief cited cases ChatGPT invented, after the chatbot told one of them the cases were real (2023)

In a passenger's personal-injury suit against the airline Avianca in the US District Court for the Southern District of New York, an opposition brief filed on 1 March 2023 cited judicial opinions that did not exist. The court found that the lawyer who did the research had used ChatGPT, which fabricated the cases, and that when he asked the chatbot whether one of them was real it replied that it had supplied real authorities that could be found on legal databases. On 22 June 2023 the court found bad faith by the two lawyers, based on their conduct after the citations were questioned, and imposed a USD 5,000 penalty jointly on them and their firm, together with letters to the client and to each judge falsely named as an author of the fake opinions.

AI system
ChatGPT
OpenAI
Occurred
1 Mar 2023 to 22 Jun 2023
Reported
27 May 2023
Event location
Unknown
What the AI did
Communicated with the person · Informed a human decision about the person
Reported harm
Legal HarmProfessional HarmFinancial Loss
Whose AI use
Their own AI use · Someone else’s AI use
Setting
Justice · Work
Evidence
AI involvement supported · Causal attribution established · 2 sources
5 claims: 5 documented. 3 open questions
People reported harmed
2 people

AI system as recorded: ChatGPT, which the court found the researching lawyer used and which fabricated the cited cases

What Happened

The brief. On 1 March 2023 the plaintiff's attorney of record filed an affirmation in opposition to the airline's motion to dismiss that cited several decisions, including one presented as Varghese v. China Southern Airlines. The airline's lawyers told the court they could not find them, and the judge wrote that six of the cases appeared to be bogus decisions with bogus quotes and internal citations.

The chatbot. The court found that a colleague of the attorney of record had used ChatGPT, which fabricated the cases, and that screenshots he filed showed him asking the chatbot whether Varghese was real and whether the other cases were fake; ChatGPT replied that it had supplied real authorities that could be found through Westlaw, LexisNexis and the Federal Reporter.

The sanctions. On 22 June 2023 the court said there is nothing inherently improper about using a reliable AI tool, but found bad faith by both lawyers because they continued to stand by the fake opinions after the court questioned them and made false and misleading statements. It imposed a USD 5,000 penalty jointly and severally on the lawyers and their firm and ordered letters to the client and to each judge falsely named as an author.

Reported harm

According to the court's sanctions opinion of 22 June 2023, two lawyers were found to have acted in bad faith and, with their firm, were ordered to pay a USD 5,000 penalty and to write to the client and to the judges falsely named as authors of the ChatGPT-invented opinions.

Outcome

Resolved

Opinion and Order on Sanctions of 22 June 2023 (S.D.N.Y., No. 1:22-cv-01461-PKC, ECF 54): bad-faith finding against the two lawyers; USD 5,000 penalty jointly and severally on them and the firm; letters to the client and to each judge falsely identified as an author of the fake opinions. Later discipline or appeal was not checked in this review.

What remains unknown

  • Whether any professional disciplinary body later acted against either lawyer, and whether the sanctions were appealed, was not checked in this review.
  • Which ChatGPT version was used; the opinion records the lawyer's prompts and the chatbot's responses only as summarised from exhibits.
  • Whether the fake citations affected the plaintiff's own claim; the separate ruling on the airline's motion to dismiss was not read.

What the evidence supports

AI involvement: supported. The sanctions opinion finds that the lawyer who researched the brief used ChatGPT, which fabricated the cited cases, and records from his filed screenshots that when he asked whether Varghese was a real case and whether the other cases were fake, ChatGPT replied that it had supplied real authorities findable on Westlaw, LexisNexis and the Federal Reporter. The fabricated authorities reached the court in the 1 March 2023 filing; the court read them, found them fake and sanctioned the two lawyers (communicated_with for the lawyer who used ChatGPT; informed_decision_about because the court's sanctions decision acted on the AI-invented authorities). The court based its bad-faith finding on the lawyers' conduct after the citations were questioned.

5 claims: 5 documented. What the statuses mean

Documented An affirmation in opposition filed on 1 March 2023 in a personal-injury suit against Avianca cited judicial decisions that did not exist.

Causal attribution. Established by the court record; BBC reports the nature of the suit.

  • storage.courtlistener.com(opens in new tab) supports · English
    'March 1, 2023 submission that first cited the fake cases'; 'On March 1, 2023, Mr. LoDuca filed an “Affirmation in Opposition” to'; 'citing non-existent cases to the Court in his Affirmation in Opposition'
  • bbc.com(opens in new tab) supports · English
    'The original case involved a man suing an airline over an alleged personal injury.'
Documented The court found that the lawyer who researched the brief had used ChatGPT and that ChatGPT fabricated the cited cases.

Causal attribution. Finding of the sanctions opinion, based on the lawyer's own testimony and filings; BBC reports his written statement.

Documented When the lawyer asked ChatGPT whether Varghese was a real case and whether the other cases were fake, ChatGPT replied that it had supplied real authorities that could be found on legal databases.

Causal attribution. The opinion describes the screenshots the lawyer filed (ECF 32-1); the exhibit itself was not read.

  • storage.courtlistener.com(opens in new tab) supports · English
    '“Is Varghese a real case” and “Are the other cases you provided fake”). (ECF 32-1.) ChatGPT'; 'responded that it had supplied “real” authorities that could be found through Westlaw,'
  • bbc.com(opens in new tab) supports · English
    ChatGPT responds again that the case is real and can be found on legal reference databases such as LexisNexis and Westlaw.
Documented On 22 June 2023 the court found bad faith by both individual lawyers, imposed a USD 5,000 penalty jointly and severally on them and their firm, and ordered letters to the client and to each judge falsely identified as an author of the fake opinions.

Causal attribution. Established by the sanctions opinion itself.

  • storage.courtlistener.com(opens in new tab) supports · English
    'the Court finds bad faith on the part of the individual Respondents based upon acts of'; 'A penalty of $5,000 is jointly and severally imposed on'; 'mail a letter individually addressed to plaintiff'; 'mail a letter individually addressed to each judge falsely identified as the author of the fake'
Documented The court said that using a reliable AI tool is not inherently improper and based the sanctions on the lawyers continuing to stand by the fake opinions after the court questioned them.

Causal attribution. Context and contrary weight: the sanction responds to the lawyers' conduct as well as to the AI output.

Sources

2 sources inspected. Sources that repeat one account do not corroborate each other.

How the sources were read, and where the events happened

Read in English by the research agent (an AI) on 2026-10-28 from the RECAP copy of the 43-page opinion (HTTP 200, text extracted with pdftotext). The hearing transcript, the April and May affidavits and the screenshot exhibit (ECF 32-1) were not read separately. Applies to s1.

Read in English by the research agent (an AI) on 2026-10-28 (HTTP 200). BBC reports the filings before the sanctions hearing. Applies to s2.

Event countries: Unknown. Affected-person countries: Unknown. Court countries: United States.

The brief was filed in, and the sanctions imposed by, the US District Court for the Southern District of New York (sanctions opinion). Where the lawyer ran his ChatGPT queries is not stated, so no event or affected-person country is recorded from the court seat.

Reviewed for publication 2026-10-28: Published because the federal sanctions opinion of 22 June 2023 documents that ChatGPT fabricated the cases cited in a filed brief, that it told the lawyer who used it the cases were real, and that the court sanctioned two lawyers and their firm after finding bad faith.

People described

Two lawyers at a New York law firm: the lawyer who used ChatGPT to research the brief and the attorney of record who filed it. Both were sanctioned in a public federal court opinion; the firm was held jointly liable.

People reported harmed in this case

2 people

1 AI participant · 1 other person harmed

Two lawyers sanctioned in the 22 June 2023 opinion: the lawyer the court found used ChatGPT (counted as the AI user) and the attorney of record who filed the brief. The firm is not counted as a person.

Counted once within this case. The same person may appear in other cases. This count does not establish AI causation.

Tags

#chatgpt#fabricated-citations#federal-court#sanctions#lawyers#new-york

Cite this case

Compiled per our published methodology: verification statuses, sourcing standards, and corrections process.

APA

NOPE. (2026). New York federal judge sanctions two lawyers whose brief cited cases ChatGPT invented, after the chatbot told one of them the cases were real (2023). AI incidents. https://nope.net/incidents/2023-new-york-federal-judge-sanctions-lawyers-over-chatgpt-invented-cases-chatbot-said-were-real

BibTeX

@misc{2023_new_york_federal_judge_sanctions_lawyers_over_chatgpt_invented_cases_chatbot_said_were_real,
  title = {New York federal judge sanctions two lawyers whose brief cited cases ChatGPT invented, after the chatbot told one of them the cases were real (2023)},
  author = {NOPE},
  year = {2026},
  howpublished = {AI incidents},
  url = {https://nope.net/incidents/2023-new-york-federal-judge-sanctions-lawyers-over-chatgpt-invented-cases-chatbot-said-were-real}
}

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