The other side filed a motion. Less than five hours later, a California lawyer filed a 20-page opposition in Boston federal court. The defense lawyers said that speed “set off red flags,” Massachusetts Lawyers Weekly reported. When they read it, they found citations to cases that said nothing of the kind, a fictitious Westlaw cite, and quotes that appeared nowhere in the cases they were attributed to.
On September 25, 2026, U.S. District Judge Angel Kelley sanctioned the lawyer, Blake J. Lindemann, under Federal Rule of Civil Procedure 11. She revoked his permission to appear in the case and ordered his firm to pay up to $10,000 of the defendants’ legal fees. We read the 19-page order in full. It is one of the most detailed rulings yet from a Massachusetts federal court on what happens when a lawyer files AI-generated work without checking it.
The case behind it
The lawsuit, Aguilar v. The Crawford Group, Inc., No. 25-cv-12395 (D. Mass.), grew out of a 2019 crash. According to the order, Sean St. Louis was driving a car rented from Enterprise by Shauna McCormick when it collided with another vehicle, killing backseat passenger Maryori Conde. St. Louis also died. Conde’s estate won a judgment of $3,260,880.33 against McCormick in state court. It then sued Enterprise-related companies and several insurers in 2025, seeking insurance coverage for that judgment. The case was moved to federal court, and Lindemann, who is licensed in California, was admitted “pro hac vice,” meaning for this case only, with a Massachusetts lawyer serving as local counsel.
What the judge found
- About half the citations were wrong. In the first brief, “approximately half of the citations in Lindemann’s memorandum of law contain an error,” Judge Kelley wrote.
- A key case said nothing about the point. The only case he cited for his main argument about Rule 12 motions “never mentions Rule 12,” the judge found. He cited it six times in one brief and again in a later one.
- A case that does not exist. In a later brief, he cited a case with Dorchester Mutual Insurance Company as the plaintiff. “After conducting a wide search, including Westlaw, Lexis, and Bloomberg, this case does not appear to exist,” the judge wrote.
- Quotes that are not there. The order lists cases cited for quotations “it does not contain,” including a Massachusetts SJC decision, and quotations altered without any indication.
- It kept happening. Errors appeared in three briefs over several months. Two were filed after the defendants had emailed him about the problem and moved for sanctions. “Although Lindemann alleges that this is an ‘isolated event,’ it unequivocally is not,” the judge wrote.
His explanations, and why they failed
According to the order, Lindemann admitted using AI to draft the first brief. He said he believed the enterprise-level AI software he used did not hallucinate cases. Lawyers Weekly reported that he described it as “AI-assisted legal research utilizing the highest-grade enterprise version of Claude.” He also said that in his haste to file before a vacation he filed an earlier draft by mistake, and he blamed later errors on a prolonged bout of influenza.
The judge was not persuaded:
- Time. He had two weeks to respond to the motion but filed in under five hours, and he returned from vacation a week before the response was due. “There was ample time for Lindemann to check his work or request an extension, if needed.”
- The “wrong draft.” “It is noteworthy that Lindemann has never submitted the correct draft.”
- Candor. When he withdrew the first brief, he gave no explanation. “For five months after the Strike Opposition was filed, Lindemann obfuscated.”
- Bad faith is not required. Quoting a 1990 First Circuit decision, the judge wrote: “Put bluntly, a pure heart no longer excuses an empty head.”
The rule: AI is allowed, unchecked AI is not
The judge did not ban AI. “There is no rule against the use of AI in researching and drafting legal papers, but it must be utilized responsibly,” she wrote. “The use of AI does not diminish an attorney’s professional and ethical obligations under Rule 11.”
Rule 11 requires that every legal argument in a filing be “warranted by existing law” or by a nonfrivolous argument for changing it. The standard is objective. A lawyer must at least be “culpably careless,” not wicked, to violate it. Quoting other courts, the judge said a lawyer using AI “must ensure that every citation and quoted passage has been independently confirmed using reliable legal sources.” It made no difference whether AI was used in the later briefs: “whether AI was used or not, Lindemann did not confirm the truthfulness of his citations.”
The sanctions
- Fees. His firm must pay the Enterprise defendants’ reasonable attorney’s fees and costs for three rounds of briefing and the sanctions motion, capped at $10,000. The parties must report by October 23, 2026 whether they agree on the amount. Lawyers Weekly reported that defense counsel says the fees exceed the cap.
- Removal. “The Court revokes Attorney Lindemann’s pro hac vice status.” The local Massachusetts lawyer remains counsel for the estate.
- A warning to local counsel. The judge did not sanction the local lawyer, because Lindemann took sole responsibility. But she reminded him of “his ongoing obligations to assist and supervise pro hac counsel.”
The order also lists sanctions other courts have used for fake citations, from fines and continuing legal education to referral to bar disciplinary authorities and dismissal of the case. A status conference is set for November 9, 2026, on the claims that remain.
What it means if you have a lawyer
The client here was the estate of a woman killed in a crash, and the brief was filed on its behalf. The judge had already dismissed the claims against the Enterprise companies and the insurers on September 2, before the sanctions order. Her order does not say the citation errors caused that result. It does show who pays when a brief goes wrong: the sanctions here fell on the lawyer and his firm, not the client.
Frequently asked questions
Can a lawyer be sanctioned for citing fake AI-generated cases in Massachusetts federal court?
Yes. In Aguilar v. The Crawford Group (D. Mass. Sept. 25, 2026), Judge Angel Kelley imposed Rule 11 sanctions, ordering payment of up to $10,000 in fees and revoking the lawyer’s pro hac vice admission.
Is it illegal for lawyers to use AI?
No. The court said there is no rule against using AI to research and draft, but the lawyer must independently confirm every citation and quotation.
What does pro hac vice mean?
Permission for a lawyer licensed in another state to appear in a single case, usually alongside a local lawyer. Revoking it removes the out-of-state lawyer from that case.
Does a lawyer have to act in bad faith to be sanctioned under Rule 11?
No. In the First Circuit, carelessness that is culpable is enough. “A pure heart no longer excuses an empty head.”
Sources: Memorandum and Order on Motion for Sanctions, Aguilar v. The Crawford Group, Inc., No. 1:25-cv-12395-AK (D. Mass. Sept. 25, 2026), ECF No. 155, read in full via govinfo.gov; Massachusetts Lawyers Weekly, October 13, 2026, including statements from defense counsel and the quoted description of the AI tool from the attorney’s filing. Fed. R. Civ. P. 11. General information about the law, not legal advice.