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Incident Tracker / United States (federal)

Coomer v. Lindell, No. 1:22-cv-01129 (D. Colo.)

·US District Court, District of Colorado·US-FEDSanctions

In the US District Court for Colorado, lawyers for MyPillow CEO Mike Lindell filed an opposition brief with nearly thirty defective citations — including non-existent cases — produced by generative AI they did not verify. Judge Nina Y. Wang sanctioned Christopher Kachouroff and Jennifer DeMaster $3,000 each under Rule 11, and later added a $5,000 penalty for a repeat.

Court
US District Court, District of Colorado
Date
2025-07-07
Who used the AI
Not recorded
AI tool
Not identified in the record
Conduct
In the defamation suit brought by former Dominion director Eric Coomer, defense counsel filed a February 2025 opposition brief containing nearly thirty defective citations, including cases that did not exist, after running the draft through generative AI without checking it. Counsel did not readily disclose the AI use when the court asked.
Outcome
Sanctions
Penalty
US$6,000
Regulatory outcome
No separate regulatory disposition recorded
Status
Verified against listed sources
Last checked
2026-09-03

What was fabricated or misused

  • Defendants’ Opposition to Motion in Limine [Doc. 283] — nearly thirty defective citations, including misquotes, misstatements, misattributions, and cases that do not exist
  • World Wide Ass’n of Specialty Programs v. Pure, Inc., 450 F.3d 1132, 1138 (10th Cir. 2006) — quoted as saying “reputation and character are inextricably intertwined”; quotation does not appear in Pure
  • United States v. Reaves, 649 F.3d 862, 867–68 (8th Cir. 2011) — did not support the proposition about evidence serving multiple purposes and implicating multiple evidentiary rules
  • Ginter v. Nw. Mut. Life Ins. Co., 576 F. Supp. 627, 630 (D. Ky. 1984) — misattributed to the District of Colorado
  • Perkins v. Fed. Fruit & Produce Co., 945 F.3d 1242, 1251 (10th Cir. 2019) — non-existent case
  • Estate of Martinelli v. City & Cnty. of Denver, No. 19-cv-02737, 2021 WL 4133804, at *6–7 (D. Colo. Sept. 10, 2021) — non-existent case
  • United States v. Hoffman, 806 F.3d 1288, 1295 (10th Cir. 2015) — non-existent case
  • Perrin v. Anderson, 784 F.2d 1040, 1045 (10th Cir. 1986) — miscited for routine admission of truthfulness evidence in defamation actions
  • United States v. Hassan, 742 F.3d 104, 133 (10th Cir. 2014) — misattributed to the Tenth Circuit; it is a Fourth Circuit case

What the court said

“[M]isquotes of cited cases; misrepresentations of principles of law associated with cited cases, including discussions of legal principles that simply do not appear within such decisions; misstatements regarding whether case law originated from a binding authority such as the United States Court of Appeals for the Tenth Circuit; misattributions of case law to this District; and most egregiously, citation of cases that do not exist.”
US District Court, District of Colorado, pp. 2-3
“Your Honor, I personally did not check it. I am responsible for it not being checked.”
Mr. Kachouroff, p. 4
“That standard was not met here with the filing of Defendants’ Opposition to Plaintiff’s Motion in Limine. [Doc. 283].”
US District Court, District of Colorado, p. 19
“a sanction of $3,000 against Christopher I. Kachouroff and the law firm of McSweeney Cynkar & Kachouroff PLLC, jointly and severally, and $3,000 against Ms. DeMaster, individually, is the least severe sanction adequate to deter and punish defense counsel in this instance.”
US District Court, District of Colorado, p. 19

Timeline

  1. Coomer filed the motion in limine that prompted defendants’ opposition.
  2. DeMaster sent Kachouroff the “final revisions” draft and a Westlaw report.
  3. Defendants filed the opposition containing nearly thirty defective citations.
  4. Coomer filed his reply in support of the motion in limine.
  5. Court issued the order to show cause after questioning counsel at the pretrial conference.
  6. Kachouroff and DeMaster submitted their response to the order to show cause.
  7. Court made the show-cause order absolute and sanctioned counsel $3,000 each.

Why this case matters

Coomer extends Mata v. Avianca from a single chatbot episode to a stacked legal-writing workflow. The order records use of multiple AI tools, a Westlaw report, exchanged drafts, and a claimed “wrong version” defence, yet the filed and final drafts still carried nonexistent cases and wrong authorities. Judge Wang treated verification as a nondelegable Rule 11 duty of each signing lawyer. The $3,000-per-lawyer sanction is also narrower than dismissal cases such as Couvrette v. Wisnovsky: the penalty targeted deterrence and did not run against the clients.

Practice note

AI-assisted drafting and citation checking need a file-level audit before filing. The signer should compare the filed PDF, the final word-processing document, any AI-generated draft, and the Westlaw or Lexis report. Each cited authority must be opened and matched to the proposition. Delegating that check to co-counsel does not satisfy Rule 11 if the signer cannot show the inquiry was reasonable.

Primary sources for this incident

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Cite this record

SafeLegalAI Global Legal AI Incident Tracker, “Coomer v. Lindell, No. 1:22-cv-01129 (D. Colo.)”, safelegalai.com/tracker/coomer-v-lindell (accessed 2026-09-16). Data: CC BY 4.0.

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