In a foreclosure case a defense lawyer used hallucinated citations in a brief. Result: $5,000 sanction. The case, as the court notes, was routine.
“Where this appeal becomes unconventional, however, is that defendant’s opening brief cites six cases which do not exist. Plaintiff identified these fabricated cases as possibly being the product of artificial intelligence (hereinafter AI), and moved for an order seeking, among other things, sanctions against defendant and defense counsel. Defendant claimed the nonexistent cases were citation or formatting errors that he would correct in his reply brief, and then opposed the motion for sanctions with more fake cases and interpretations for existing cases that are at best strenuously attenuated, and at worst entirely inapposite. Defendant’s subsequent reply brief acknowledged that his “citation of fictitious cases is a serious error” and that they are “problematic,” but failed to offer any corrections or further explanation as previously stated. He then proceeded to include more fake cases and false legal propositions in two subsequent letters to this Court that requested judicial notice of a bankruptcy stay. In examining the propriety of defendant’s previously filed papers, more nonexistent cases were discovered in a motion that granted affirmative relief to defendant. Defense counsel reluctantly conceded during oral argument that he used AI in the preparation of his papers and, although he told the Court that he checked his papers, the filings themselves demonstrate otherwise. In total, defendant’s five filings during this appeal include no less than 23 fabricated cases, as well as many other blatant misrepresentations of fact or law from actual cases.
Although other state and federal courts have had the occasion to address the misuse of AI in legal papers, this Court has not yet had that opportunity. In doing so, we recognize that, as did the shift from digest books to online legal databases, generative artificial intelligence (hereinafter GenAI) represents a new paradigm for the legal profession, one which is not inherently improper, but rather has the potential to offer benefits to attorneys and the public — particularly in promoting access to justice, saving costs for clients and assisting courts with efficient and accurate administration of justice (see Wadsworth v. Walmart Inc., 348 FRD 489, 492-493 [D Wyo 2025]; Mata v. Avianca, Inc., 678 F Supp 3d 443, 448 [SD NY 2023]).[4] At the same time, attorneys and litigants must be aware of the dangers that GenAI presents to the legal profession. At the forefront of that peril are AI “hallucinations,” which occur when an AI database generates incorrect or misleading sources of information due to a “variety of factors, including insufficient training data, incorrect assumptions made by the model, or biases in the data used to train the model” (What are AI Hallucinations?,https://cloud.google.com/discover/what-are-ai-hallucinations [last accessed Jan. 6, 2026]; see generally United States v. Google LLC, ___ F Supp 3d ___, ___, 2025 WL 2523010, *15, 2025 US Dist LEXIS 170459, *74 [D DC, Sept. 2, 2025, Nos. 20-cv-3010 (APM), 20-cv-3715 (APM)]).[5] Hallucinated cases may look like a real case because they include familiar-looking reporter information, but their citations lead to cases with different names, in different courts and on different topics — or even to no case at all (see Sanders v. United States, 176 Fed Cl 163, 168-169 [Fed Cl 2025]). Even where GenAI provides accurate case citations, it nonetheless may misrepresent the holdings of the cited cases — often in favor of the user supplying the query (see Green Bldg. Initiative, Inc. v. Peacock, 350 FRD 289, 292 [D Ore 2025]; Kruglyak v. Home Depot U.S.A., Inc., 774 F Supp 3d 767, 770 [WD Va 2025]; see also Matter of Richburg, 671 BR 918, 924 n 11 [Bankr D SC 2025]).[6]
Courts throughout the country which have been confronted with AI-generated authorities have concluded that filing papers containing hallucinated cases and fabricated legal authorities may be sanctionable (see generally OTG New York, Inc. v. OTTOGI Am., Inc., 2025 WL 2671460, *2-3, 2025 US Dist LEXIS 183358, *7-8 [D NJ, Sept. 18, 2025, No. 24-cv-07209 (BRM) (JRA)]). This includes where the fake citations stand for accurate legal principles (see Ader v. Ader, 87 Misc 3d 1213[A], *2 [Sup Ct, NY County 2025]; see also United States v. McGee, ___ F Supp 3d ___, ___, 2025 WL 2888065, at *7, 2025 US Dist LEXIS 201350, * 19; Johnson v. Dunn, 2025 WL 2086116, *16, US Dist LEXIS 141805, *45-46 [ND Ala, July 23, 2025, No. 2:21-cv-1701-AMM]), as there are many harms associated with the submission of fake cases that extend beyond merely wasting the time and money of the opposing party, but also in taking up the court’s resources to evaluate and resolve the deception (see Mata v. Avianca, Inc., 678 F Supp 3d at 448).
In New York, courts have discretion to award costs or impose financial sanctions against an attorney or party for engaging in frivolous conduct (see 22 NYCRR 130-1.1[a], [b]; WFE Ventures, Inc. v. GBD Lake Placid, LLC, 197 AD3d 824, 836 [3d Dept 2021]). “[C]onduct is frivolous if: (1) it is completely without merit in law and cannot be supported by a reasonable argument for an extension, modification or reversal of existing law; (2) it is undertaken primarily to delay or prolong the resolution of the litigation, or to harass or maliciously injure another; or (3) it asserts material factual statements that are false” (22 NYCRR 130-1.1[c]). “In determining whether the conduct undertaken was frivolous, the court shall consider, among other issues the circumstances under which the conduct took place, including the time available for investigating the legal or factual basis of the conduct, and whether or not the conduct was continued when its lack of legal or factual basis was apparent, should have been apparent, or was brought to the attention of counsel or the party” (22 NYCRR 130-1.1[c]; see Matter of Minister, Elders & Deacons of Refm. Prot. Dutch Church of City of N.Y. v. 198 Broadway, 76 NY2d 411, 414 [1990]). Moreover, rule 3.3 of the Rules of Professional Conduct provides that “[a] lawyer shall not knowingly . . . make a false statement of fact or law to a tribunal or fail to correct a false statement of material fact or law previously made to the tribunal by the lawyer” (Rules of Prof Conduct [22 NYCRR 1200.0] rule 3.3[a][1]). Sanctions may be appropriate for frivolous and meritless appeals (see Bell v. State of New York, 96 NY2d 811, 812 [2001]), and are a common consequence for misuses of judicial process which unnecessarily divert “the time and attention of . . . [the] Judges of this State” (Matter of Minister, Elders & Deacons of Refm. Prot. Dutch Church of City of N.Y. v. 198 Broadway, 76 NY2d at 415; see generally Engel v. CBS, Inc., 93 NY2d 195, 207 [1999]; Mata v. Avianca, Inc., 678 F Supp 3d at 448).
Here, defendant submitted at least 23 fabricated legal authorities across five filings during the pendency of this appeal.[7] He has also misrepresented the holdings of several real cases as being dispositive in his favor — when they were not.[8] It is axiomatic that submission of fabricated legal authorities is completely without merit in law and therefore constitutes frivolous conduct (see 22 NYCRR 130-1.1[c][1]). It cannot be said that fabricated legal authorities constitute “existing law” so as to provide a nonfrivolous ground for extending, modifying or reversing existing law (see 22 NYCRR 130-1.1[c][1]; see generally Wadsworth v. Walmart Inc., 348 FRD at 495; Mata v. Avianca, Inc., 678 F Supp 3d at 461). Defense counsel acknowledged during oral argument that the papers were his own, and, nevertheless, “[b]y signing a paper, an attorney or party certifies that, to the best of that person’s knowledge, information and belief, formed after an inquiry reasonable under the circumstances . . . the presentation of the paper or the contentions therein are not frivolous” (22 NYCRR 130-1.1a[b][1]). However, the excuse for fabricated legal authorities offered by defendant in his papers is incredible. Moreover, during oral argument defense counsel estimated that 90% of the citations he used were accurate, which, even if it were true, is simply unacceptable by any measure of candor to any court (see Rules of Prof Conduct [22 NYCRR 1200.0] rule 3.3[a][1]). Where we are most troubled is that more than half of the fake cases offered by defendant came after he was on notice of such issue, whereby his reliance on fabricated legal authorities grew more prolific as this appeal proceeded — despite it being apparent to him that such conduct lacked a legal basis (see Ader v. Ader, 87 Misc 3d 1213[A], *1; see also 22 NYCRR 130-1.1[c]; Rules of Prof Conduct [22 NYCRR 1200.0] rule 3.3[a][1]). Rather than taking remedial measures or expressing remorse, defense counsel essentially doubled down during oral argument on his reliance of fake legal authorities as not “germane” to the appeal.[9]
Turning to the appropriate sanction, courts must consider that sanctions are both retributive, in that they punish past conduct, but are also “goal oriented, in that they are useful in deterring future frivolous conduct not only by the particular parties, but also by the [b]ar at large” (Levy v. Carol Mgt. Corp., 260 AD2d 27, 34 [1st Dept 1999]). In doing so, courts around the country have imposed sanctions ranging from warnings to tens of thousands of dollars to attorneys who have submitted AI hallucinated legal authorities and false propositions (see e.g. Cojom v. Roblen, LLC, 2025 WL 3205930, *4, 2025 US Dist LEXIS 225325, *9-10 [D Conn, Nov. 17, 2025, No. 3:23-CV-1669 (JCH)] [involving three nonexistent cases; total sanction $500]; Hall v. Academy Charter Sch., 2025 WL 2256653, *5-6, 2025 US Dist LEXIS 152628, *14-16[ED NY, Aug. 7, 2025, No. 2:24-cv-08630-JMW] [involving three nonexistent cases; warning]; Lacey v. State Farm Gen. Ins. Co., 2025 WL 1363069, *5, 2025 US Dist LEXIS 90370, *13 [CD Cal, May 5, 2025, No. CV 24-5205 FMO (MAAx)] [involving nine incorrect citations and two authorities that did not exist by attorneys in two law firms; total sanctions $31,100]). Such broad range reflects a constellation of factors surrounding the conduct of the attorney or party offering such fabricated legal authorities, including the number of fake cases or propositions, whether there were fake quotes, if the submitter continued to use or create more fabricated authorities across other filings in the same proceeding after being on notice of the misconduct, there was an admission of the error, there was remorse and the extent of the impact that the fabricated legal authorities had on the proceedings. Considering these factors, courts in cases involving comparable misconduct by defense counsel have imposed significant sanctions (see e.g. Noland v. Land of the Free, L.P., 114 Cal App 5th 426, 449, 336 Cal Rptr 3d 897, 912 [Cal Ct App 2025] [involving 21 fabricated case citations and quotations by attorney; total sanction $10,000]; Mid Cent. Operating Engrs. Health & Welfare Fund v. HoosierVac LLC, 2025 WL 1511211, *2, 2025 US Dist LEXIS 100748, *3-4 [SD Ind, May 28, 2025, No. 2:24-cv-00326-JPH-MJD] [involving six nonexistent cases across multiple filings; total sanction $6,000]; Kruse v. Karlen, 692 SW3d 43, 50-54 [Mo Ct App 2024] [involving 22 fabricated case citations and multiple statutory misstatements by attorney; total sanction $10,000]).
Accordingly, recognizing this as the first appellate-level case in New York addressing sanctions for the misuse of GenAI, we find the imposition of a monetary sanction on defense counsel Joshua A. Douglass in the amount of $5,000 to be appropriate under the circumstances, with the further goal of deterring future frivolous conduct by defendant and the bar at large (see Levy v. Carol Mgt. Corp., 260 AD2d at 34). To be clear, attorneys and litigants are not prohibited from using GenAI to assist with the preparation of court submissions. The issue arises when attorneys and staff are not sufficiently trained on the dangers of such technology, and instead erroneously rely on it without human oversight. As with the work from a paralegal, intern or another attorney, the use of GenAI in no way abrogates an attorney’s or litigant’s obligation to fact check and cite check every document filed with a court. To do otherwise may be sanctionable, depending on the facts and particular circumstances of each case.”
Citation: 2026 NY Slip Op 00040
Deutsche Bank National Trust Company, as Trustee, Respondent,
v.
Jean LeTennier, Also Known as Jean Michel LeTennier and Jean M. LeTennier, Appellant, et al., Defendants.









