AI Hallucination Cases

"The first reason I issue sanctions stems from [Counsel]'s claim of ignorance—he asserts he didn't know the use of AI in general and ChatGPT in particular could result in citations to fake cases. Mr. Nield disputes the court's statement in Wadsworth v. Walmart Inc. (D. Wyo. 2025) that it is "well-known in the legal community that AI resources generate fake cases." Indeed, [Counsel] aggressively chides that assertion, positing that "in making that statement, the Wadsworth court cited no study, law school journal article, survey of attorneys, or any source to support this blanket conclusion."

I find [Counsel]'s position troubling. At this point, to be blunt, any lawyer unaware that using generative AI platforms to do legal research is playing with fire is living in a cloud."

[...]

"If anything, [Counsel]’s alleged lack of knowledge of ChatGPT’s shortcomings leads me to do what courts have been doing with increasing frequency: announce loudly and clearly (so that everyone hears and understands) that lawyers blindly relying on generative AI and citing fake cases are violating Bankruptcy Rule 9011 and will be sanctioned"

Counsel submitted a response to an Order to Show Cause that included a false quote attributed to none other than Mata v. Avianca, a case about hallucinations.

In May, the court asked Counsel to show cause why they should not be sanctioned for filing briefs with hallucinations - especially since they continued filing hallucinated submissions after being warned about it.

In their Answer, Counsel revealed that "specific citations and quotes in question were inadvertently derived from internal draft text prepared using generative AI research tools designed to expedite legal research and brief drafting".

In the Order, the court noted that Counsel "was not candid to the Court when confronted about his use of AI, stating that some of these documents were “prepared under time constraints,” when he had nearly two more weeks before the deadline to submit his responses." The judge was also unimpressed by Counsel's attempt to shift the blame to a paralegal.

Finally, in the fee dispute order, the court cited this database to point out that its approach to award costs and fees was appropriate, especially given the egregiousness of the claimant's conduct in this case. The judge also took into account "the significant, if indirect, monetary losses that may arise from nonmonetary sanctions in other cases, such as loss of business and loss of reputation, or the monetary loss borne by a client when a motion or even an entire case is adversely decided due to counsel’s misuse of AI."

Plaintiff's Counsel cited nine non-existent cases in a response to a motion to dismiss, which were generated using AI software. The court found this to be a violation of Rule 11, as the citations were not checked for accuracy. Counsel admitted the error, apologized, and explained the circumstances, including staff transitions and the use of AI. The court imposed a $1000 sanction, required Mr. Braddy to attend a CLE course on AI ethics, and ordered reimbursement of Defendant's attorney fees and costs.

Counsel confessed having Claude Sonnet 4 to draft a legal submission, which included fabricated quotations from legal authorities. Counsel said he was pressed by time.

After holding that there is "no reason to distinguish between the submission of fabricated cases and the submission of fabricated quotations from real cases. In both postures, the attorney seeks to persuade the Court using legal authority that does not exist", the court held that Mr. Desmarais had violated Rule 11 of the Federal Rules of Civil Procedure by failing to verify the accuracy of the AI-generated content. Counsel was found to have acted in subjective bad faith, as he was aware of the potential for AI to hallucinate legal citations and failed to take corrective action even after the government pointed out the errors.

The court imposed a $1,000 monetary sanction and required Counsel to complete a CLE course on the ethical use of AI in legal practice and notify his client of the issue.

Prior Order to Show Cause available here.

After reviewing - and dismissing - the factual allegations made by Counsel, and noting that they had submitted errata in parallel cases (dealing with other fabricated citations), the court swiftly concluded that they "have violated Rule 11 because they were not reasonable in certifying that the claims, defenses, and other legal contentions contained in Defendants’ Opposition to Motion in Limine [Doc. 283] were warranted by existing law or by a nonfrivolous argument for extending, modifying, or reversing existing law or for establishing new law."

Both counsel were sanctioned with a 3,000 USD fine, payable to the court.

"Further, these inaccuracies signal that Plaintiff's counsel may have used AI to assist in the drafting of Plaintiff's Response (or otherwise counsel produced exceptionally sloppy work). In this regard, this Court's Chambers Rules include “Disclosure and Certification Requirements” for use of “Generative Artificial Intelligence” and expressly provide that an attorney or party must disclose in any document to be filed with the Court “that AI was used and the specific AI tool that was used” and to “certify in the document that the person has checked the accuracy of any portion of the document drafted by generative AI, including all citations and legal authority.” See id.6 No such disclosure and certification has been made in this case. The Court's Rules further provide that an attorney will be responsible for the contents of any documents prepared with generative AI, in accordance with Rule 11 of the Federal Rules of Civil Procedure, and that the failure to make the disclosure and certification “may result in the imposition of sanctions.”"

The court noted that:

"both Lehr-Guthrie's and McDonald's briefs are replete with errors in their citations to case authority, such as repeated citation errors, references to nonexistent quotes, and incorrect statements about the cases (for instance, as noted above, the two cases McDonald cited for a proposition relating to the duty of impartiality don't even reference that duty). This suggests to us that the briefs may have been drafted with the use of generative artificial intelligence (GAI). “[U]sing a GAI tool to draft a legal document can pose serious risks if the user does not thoroughly review the tool's output.” Al-Hamim v. Star Hearthstone, LLC, 2024 COA 128, ¶ 32. Self-represented litigants must be particularly careful, as they “may not understand that a GAI tool may confidently respond to a query regarding a legal topic ‘even if the answer contains errors, hallucinations, falsehoods, or biases.’ ” Id. (citation omitted).4 We advise the parties that errors caused by GAI in future filings may result in sanctions. See id. at ¶ 41. "

The court warned that future errors caused by AI could result in sanctions.

"In a prior order, we struck portions of Walker's brief that included citations to nonexistent cases. We note that the arguments raised would not have changed the outcome of the appeal in any event. "

"Compounding the problem, what generative AI lacks in precision, it more than makes up for in speed. Litigants who simply file the material that AI tools generate, without carefully reviewing it first for accuracy, have the potential to swamp courts with what appear at first glance to be legal arguments built on law and precedent, but which are in fact nothing of the sort. And not only are these problems in their own right, but they also heighten the two concerns the Court highlighted above—that defendants will be forced to spend more time and incur more costs parsing through copious baseless filings to defend an action, and that Courts will waste precious time doing the same in ruling on motions and moving matters along."

(Plaintiff acknowledged use of ChatGPT in a subsequent filing)

Plaintiff was eventually designated as vexatious litigant and his case dismissed with prejudice.

Defendant Holly Nelson, appearing pro se, filed a motion to dismiss that included a fabricated case citation, Finch v. Smith, which does not exist. The court inferred that Nelson used AI to draft the motion without verifying the accuracy of the citations. The court issued an order to show cause, requiring Nelson to justify why her filing does not violate Rule 11, or alternatively, to withdraw her motion. If she fails to do so, the court intends to strike her motion entirely.

Fake citation, in this brief, was to : Moms Against Poverty v. Dep’t of State, 2022 WL 17951329, at *3 . Case docket can be found here.

Counsel later confirmed having used ChatGPT and apologised.

" After the trial court entered a final judgment and decree of divorce, Nimat Shahid (“Wife”) filed a petition to reopen the case and set aside the final judgment, arguing that service by publication was improper. The trial court denied the motion, using an order that relied upon non-existent case law."

"We are troubled by the citation of bogus cases in the trial court's order. As the reviewing court, we make no findings of fact as to how this impropriety occurred, observing only that the order purports to have been prepared by Husband's attorney, Diana Lynch. We further note that Lynch had cited the two fictitious cases that made it into the trial court's order in Husband's response to the petition to reopen, and she cited additional fake cases both in that Response and in the Appellee's Brief filed in this Court. "

In the case of Crespo v. Tesla, Inc., the pro se plaintiff, Leonardo Crespo, submitted discovery motions containing fabricated case citations and a false quote, which were identified as potentially generated by AI. The court ordered Crespo to show cause for these submissions and admitted to using AI in his filings. The court acknowledged Crespo's candor and imposed sanctions requiring him to apologize to the defendant's counsel and pay reasonable attorney's fees incurred by the defendant in addressing the fake citations.

(In a subsequent ruling, the court averred that the reasonable fees amount was 921 USD.)

Plaintiff Ravel Ferrera Parra, proceeding pro se, filed a lawsuit against the United States alleging financial harm due to misconduct by various judicial and governmental entities. The court dismissed the case for lack of jurisdiction, as the claims were not within the court's purview.

The court noted that Plaintiff's filings appeared to be assisted by AI, as evidenced by the rapid filing of responses tell-tale language ("Would you like additional affidavits, supporting exhibits, or further refinements before submission?"), the inclusion of fabricated case citations. "While Plaintiff’s use of AI, by itself, does not violate this Court’s Rules, Plaintiff’s citation to fake cases does."

The court further pointed out that:

"“It is no secret that generative AI programs are known to ‘hallucinate’ nonexistent cases.” Sanders, 176 Fed. Cl. at 169 (citation omitted). That appears to have happened here. When searching the Federal Claims Reporter for “Tucker v. United States, 71 Fed. Cl. 326 (2006),” Plaintiff’s citation brings the Court to the third page of Grapevine Imports, Ltd. v. United States, 71 Fed. Cl. 324, 326 (2006), a real tax case from this Court. Similarly, the AI used by Plaintiff in Sanders v. United States, 176 Fed. Cl. 163, 169 (2025) also made up a citation to a case called Tucker v. United States. Perhaps both AI programs hallucinated this case name based on the Tucker Act, this Court’s jurisdictional statute. Regardless, here, as in Sanders, the citation to a case called Tucker v. United States does not exist."

The court warned Plaintiff about the risks of using AI-generated content without verification but did not impose sanctions.

The court observed that the original motion to remand filed pro se by the plaintiff contained non-existent case law and falsified quotations. Although the court did not impose sanctions in this instance, it warned that future use of fake legal authority would result in a show cause order, including against the Counsel who later joined the case.

Penalty decided in an order from the next day.

"Before addressing the merits of Schoene’s motion, the Court notes that Schoene cited several cases in her reply brief to support her motion to amend, including Butler v. Oregon, 218 Or. App. 114 (2008), Curry v. Actavis, Inc., 2017 LEXIS 139126 (D. Or. Aug. 30, 2017), Estate of Riddell v. City of Portland, 194 Or. App. 227 (2004), Hampton v. City of Oregon City, 251 Or. App. 206 (2012), and State v. Burris, 107 Or. App. 542 (1991). These cases, however, do not exist. Schoene’s false citations appear to be hallmarks of an artificial intelligence (“AI”) tool, such as ChatGPT. It is now well known that AI tools “hallucinate” fake cases. See Kruse v. Karlen, 692 S.W.3d 43, 52 (Mo. Ct. App. 2024) (noting, in February 2024, that the issue of fictitious cases being submitted to courts had gained “national attention”).6 In addition, the Court notes that a basic internet search seeking guidance on whether it is advisable to use AI tools to conduct legal research or draft legal briefs will explain that any legal authorities or legal analysis generated by AI needs to be verified. The Court cautions Schoene that she must verify the accuracy of any future citations she may include in briefing before this Court and other courts"

Plaintiff's counsel in the case of Mintvest Capital, LTD v. NYDIG Trust Company, et al., was found to have included numerous non-existent cases, false quotations, and misrepresented precedents in their filings. The errors were attributed to the use of the AI tool 'Claude' without proper verification. The court recommended sanctions under Rule 11, requiring the attorney to pay the defendants' attorney fees related to the faulty submissions. The court emphasized the need for attorneys to ensure the accuracy of citations, especially when using AI tools, to maintain professional standards.

After other side pointed out that all authorities cited were fictitious, Counsel admitted it in brief. The court seemingly did not react.

"Artificial intelligence may ultimately prove a helpful tool to assist pro se litigants in bringing meritorious cases to the courts. In that way, artificial intelligence has the potential to contribute to the cause of justice. However, accessing any beneficial use of artificial intelligence requires carefully understanding its limitations. For example, if merely asked to write an opposition to an opposing party’s motion or brief, or to respond to a court order, an artificial intelligence program is likely to generate such a response, regardless of whether the response actually has an arguable basis in the law. Where the court or opposing party was correct on the law, the program will very likely generate a response or brief that includes a false statement of the law. And because artificial intelligence synthesizes many sources with varying degrees of trustworthiness, reliance on artificial intelligence without independent verification renders litigants unable to represent to the Court that the information in their filings is truthful."

"In Rutella's reply in support of his motion to vacate, he cites Green v. John H. Streater, Jr., 666 F.2d 119 (3d Cir. 1981). DE [69-1] at 8. When the Court was unable to locate Green or any case resembling it, the Court instructed Rutella's attorney, Kevin Krupnick, to either submit a copy of the case or show cause why he should not be sanctioned. See Electronic Order dated May 22, 2025. Krupnick admitted that he fabricated the Green case and claimed that he used it as a “placeholder” in a draft. DE [70-1]. It is implausible that an attorney would cite a case as specific as “Green v. John H. Streater, Jr., 666 F.2d 119 (3d Cir. 1981)” – which Krupnick admits does not exist – as a “placeholder” that he intended to replace. This is particularly true here, as Plaintiff had already cited the case that he subsequently claimed he intended to use. See DE [69-1] at 3 (citing Peralta v. Heights Med. Ctr., 485 U.S. 80 (1988)). Although Krupnick's conduct raises questions of his adherence to Fed. R. Civ. P. 11 (as he himself concedes), given the Court's recommendation that Rutella's motion to vacate be denied, the Court declines to recommend further action with respect to Rutella's misleading submission. "

"Regardless of whatever resources are used to prepare a party’s brief, every attorney has an ongoing responsibility to review and ensure the accuracy of filings with this and other courts. This includes checking that all case law cited in a brief actually exists and supports the points being made. It is never acceptable to rely on software or technology—no matter how advanced—without reviewing and verifying the information. The use of AI or other technology does not excuse carelessness or failure to follow professional standards.

Technology can be helpful, but it cannot replace a lawyer’s judgment, research, or ethical responsibilities. The practice of law changes with the use of new technology, but the core duties of competence and candor remain the same. Lawyers must adapt to new tools without lowering their standards."

" Plaintiffs identify fictitious quotes and citations in their briefing to support their arguments. For example, Plaintiffs purport to quote language from S.H. Hold v. United States, 853 F.3d 1056, 1064 (9th Cir. 2017) and Green v. United States, 630 F.3d 1245, 1249 (9th Cir. 2011). (Reed 2, Dkt. No. 23 at 6.) However, the quoted language is nowhere found in those cases. Plaintiffs also cite to a case identified as “Horne v. Potter, 557 F.3d 953, 957 (9th Cir. 2009).” (Id. at 7.) That citation, however, is for a case titled Bell v. The Hershey Company. Plaintiffs appear to acknowledge they offered fictitious citations. (See Reed 2, Dkt. No. 27.) Plaintiffs are cautioned that providing fictitious cases and quotes will lead to sanctions. "

" This Court's local rules permit the use of generative artificial intelligence programs, but all parties, including pro se parties, must certify “that to the extent such a program was used, a human signatory of the document verified the accuracy of all generated text, including all citations and legal authority,” NECivR 7.1(d)(4)(B). The plaintiff's brief contains no such certification, nor does the plaintiff deny using artificial intelligence. See filing 27 at 9.
From the Court's review of the plaintiff's brief, most citations are not hallucinatory. But the plaintiff undeniably cites to cases that do not support the stated legal proposition. For example, the plaintiff asserts that “courts must ‘accept all factual allegations in the complaint as true.’ ” Filing 22 at 3. He attributes the quoted language to Braden v. Wal-Mart Stores, Inc., 588 F.3d 585, 595 (8th Cir. 2009). The quote is a boilerplate recitation of the standard on a motion to dismiss, and any number of cases contain that exact language—but not Braden, the case to which the plaintiff attributed the quote.

The plaintiff characterizes the mismatched citations as “[t]ypographical errors or minor misstatements.” Filing 27 at 9. That may be true for some of the mistakes—for example, the case Foman v. Davis, 371 U.S. 178 (1962) is correctly cited, and it immediately precedes a citation for the nonexistent “Foman v. Arnold,” which might be explained as a typographical error. See filing 22 at 13. But not all the mistakes are so innocent, such as the plaintiff's citation to the nonexistent “Brown v. Maple Tree Homes, Inc.,” purported to be a Nebraska case, the citation to which directs to a Wisconsin Supreme Court decision. Filing 22 at 12. This mistake resembles the hallucinatory citations seen in other cases, and is a mistake the plaintiff had an obligation to correct before filing his brief. See Strong v. Rushmore Loan Mgmt. Servs., LLC, No. 8:24-cv-352, 2025 WL 100904, at *6 (D. Neb. Jan. 15, 2025).

The plaintiff also asserts that while the citations may be erroneous, the statements of law are not. The Court agrees that the plaintiff made no substantive misrepresentations of law, so striking the brief is not the appropriate remedy. However, the plaintiff should take notice of the fact that such conduct, if repeated, could subject him to sanctions, even as a pro se litigant. See Ferris v. Amazon.com Servs., LLC, No. 3:24-cv-304, 2025 WL 1122235, at *2 (N.D. Miss. Apr. 16, 2025); Rubio v. D.C., No. 23-cv-719, 2024 WL 4957373, at *4 (D.D.C. Dec. 3, 2024); Vargas v. Salazar, No. 4:23-CV-4267, 2024 WL 4804091, at *3 (S.D. Tex. Nov. 1, 2024); Martin v. Hawai‘i, No. 24-cv-294, 2024 WL 3877013, at *2 (D. Haw. Aug. 20, 2024)."

"The pervasive misrepresentations of the law in Lucas' filings cannot be tolerated. It serves to make a mockery of the judicial process. It causes an enormous waste of judicial resources to try to find cited cases that do not exist and to determine whether a cited authority is relevant or binding, only to determine that most are neither.

In like fashion, Lucas' adversaries also must run to ground the nonexistent cases or address patently irrelevant ones. The adversaries must thus incur needless legal fees and expenses caused by Lucas' pervasive citations to nonexistent or irrelevant cases.

[...]

However, as previously noted Lucas appears to be judgment proof so monetary sanctions likely will not deter her from the abusive practices reflected in her filings and in her previously announced, consistently followed, abuse of the litigation proceedings created by the Individuals with Disabilities Education Act, 20 U.S.C. § 1400, et seq. (“IDEA”). So, the Court must find some other way to protect the interests of justice and to deter Lucas from the abuses which have come to mark her approach to participation as a defendant in the judicial process.

In this case, the most appropriate remedy is to strike Lucas' filings where they are burdensome by virtue of volume and exceed permitted page limits, where they are not cogent or understandable (when given the generous latitude afforded pro se litigants), and where they misrepresent the law by citing nonexistent or utterly irrelevant cases."

In a subsequent Opinion, the court declined to reconsider or review its findings, pointing out that:

"To begin, it is unclear what Lucas means by "contested" citations. The citations that the Court found to not exist are not "contested." They simply do not exist. There is no contesting that fact because the Court checked each citation that was referenced in its MEMORANDUM OPINION, exactly as Lucas cited them (and through other research means), and could not find any citation that matched what Lucas cited. That research demonstrates that the Court's

findings are, in fact, supported rather than "[u]nsupported." Id.

Then, in no way did the Court "wrongly assume[]" that these citations to nonexistent legal authority were "'fabricated' due to the use of generative AI." Id. The Court meticulously checked every citation that it held did not exist in those decisions. Those decisions were not based on "assumptions" but, instead, on the fact that either (1) no case existed under the reporter citation, case name, or quotation that Lucas used, or (2) a case with the reporter citation did exist but was to an entirely different case than the one cited by Lucas and had no relevancy to the issues of this case. ECF No. 170, at 520. And, there was no incorrect assumption that those nonexistent legal authorities were generated, hallucinated, or fabricated by AI because Lucas admitted, on the record, to using AI when writing her filings with the Court. The fact that her citations to nonexistent legal authority are so pervasive, in volume and in location throughout her filings, can lead to only one plausible conclusion: that an AI program hallucinated them in an effort to meet whatever Lucas' desired outcome was based on the prompt that she put into the AI program. As the Court described in its MEMORANDUM OPINION, this is becoming an alarmingly prevalent occurrence common

to AI programs. Id. at 23-26. It is exceedingly clear that it occurred here.

[...]

The MOTION also complains that the Court did not give Lucas an "opportunity to verify or correct citations." Id.

Wholly apart from the fact that it is the litigant's (pro se or represented) burden to verify citations, there is no reason to have accorded Lucas the opportunity to verify because the problem was extensive and pervasive across at least six filings. Moreover, the Court actually did what should have been done before the MOTION was filed by determining that those citations do not exist. No further verification is necessary. And, after a diligent search, if the Court could not find the legal authorities that Lucas purported to rely upon and present as real and binding, it is a folly to believe that Lucas' efforts at "correction" would have returned anything different. Further, she could have taken the opportunity in this MOTION to go through—citation by citation—and "verify" or "correct" them to demonstrate to the Court that its findings were, in fact, incorrect, rather than just baldly and without evidence claiming them to be so. She did not do that."

In an earlier decision, the court had already warned the plaintiff against "any further legal misrepresentations in future communications".

AI Use

Attorneys for Wright County submitted a memorandum in support of a motion for summary judgment that contained five case citations generated by artificial intelligence; these citations did not refer to actual judicial decisions. Much of the brief appeared to be AI-written. The attorney who signed and filed the brief, acknowledged that the cited authorities did not exist and that much of the brief was drafted by AI.

Ruling/Sanction

The Court found Counsel's conduct violated Rule 11.02(b) of the Minnesota Rules of Civil Procedure, as fake case citations cannot support any legal claim and there's an affirmative duty to investigate the legal underpinnings of a pleading. The Court found no merit in Counsel's defense, noting that the substitute cases she offered did not support the legal contentions in the brief, and the brief demonstrated a fundamental misunderstanding of legal standards. The Court did not find her insinuation that another, accurate motion document existed to be credible.

Although the Court considered summarily denying the County's motion as a sanction, it ultimately denied the motion on its merits in a concurrent order because the arguments were so clearly incorrect.

The Court declined to order further monetary sanctions, believing its Order to Show Cause and the current Order on Sanctions were sufficient to deter Counsel from relying solely on AI for case citations or legal conclusions in the future. However, the Court referred the matter concerning Counsel's conduct to the Minnesota Lawyers Professional Responsibility Board for further review, as the submission of an AI-generated brief with fake citations raised questions regarding her honesty, trustworthiness, and fitness as a lawyer.

The underlying motion was later withdrawn, with the result that the tentative ruling was not adopted.

(Earlier report and recommendation can be found here.)

AI Use

Counsel admitted at a show cause hearing that he used generative AI tools to draft multiple briefs and did not verify the citations provided by the AI, mistakenly trusting their apparent credibility without checking.

Hallucination Details

Three distinct fake cases across filings. Each was cited in a separate brief, with no attempt at Shepardizing or KeyCiting.

Ruling/Sanction

The Court recommended a $15,000 sanction ($5,000 per violation), with the matter referred to the Chief Judge for potential additional professional discipline. Counsel was also ordered to notify Hoosiervac LLC’s CEO of the misconduct and file a certification of compliance.

Eventually, the court fined Counsel $6,000, stressing that this was sufficient.

Key Judicial Reasoning

The judge stressed that "It is one thing to use AI to assist with initial research, and even nonlegal AI programs may provide a helpful 30,000-foot view. It is an entirely different thing, however, to rely on the output of a generative AI program without verifying the current treatment or validity—or, indeed, the very existence—of the case presented. Confirming a case is good law is a basic, routine matter and something to be expected from a practicing attorney. As noted in the case of an expert witness, an individual's "citation to fake, AI-generated sources . . . shatters his credibility." See Kohls v. Ellison, No. 0:24-cv-03754-LMP-DLM, Doc. 46 at *10 (D. Minn. Jan. 10, 2025)."

Counsel's explanation of what happened can be found here.

" The Court has serious reason to believe that Plaintiff used artificial intelligence tools to assist in drafting her objection. While the use of such tools is not prohibited, artificial intelligence often cites to legal authorities, like Cabrera, that do not exist. Continuing to cite to non-existent cases will result in sanctions up to and including dismissal. "