Sanction teardown · D. Colorado, USA · 2025-11-14
Matthew Lewis v. Eagle County Government
What happened
In D. Colorado, USA, a filing relied on an unnamed/unconfirmed AI tool to help draft legal argument. The court identified the following problems with the citations in that filing:
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Outdated Advice (Repealed Law)Court noted the original Complaint relied on a pre-2011 regulatory '20% rule' that was amended in 2011 and therefore was a superseded/regulatory error.
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Fabricated (Case Law)Court found this citation does not correspond to any existing opinion; counsel later conceded the citation, as presented, was fictitious.
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Fabricated (Case Law)Court found this citation, as presented, does not exist and was included in the First Amended Complaint.
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Fabricated (Case Law)Court determined this cited decision, in the form presented in the pleading, does not exist.
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Fabricated (Case Law)Court concluded this citation as presented does not correspond to an existing case; included in First Amended Complaint.
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Misrepresented (Case Law)Court observed counsel cited Huff for a proposition it does not support; Huff holds §203(y) does not require actual fire suppression, cutting against Plaintiff's asserted proposition.
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Misrepresented (Case Law)Court determined this case is inapposite to the §203(y) proposition for which it was cited (does not involve §203(y)).
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Misrepresented (Case Law)Court found these cited Ninth Circuit decisions do not support the proposition they were cited for (they did not arise on motions to dismiss as claimed).
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Misrepresented (Case Law)Court found counsel misused this Ninth Circuit authority; it does not support the asserted proposition at the pleading stage.
Which AI tool
an unnamed/unconfirmed AI tool. Note: Charlotin's public database records tool attribution only where a court order, brief, or reporting on the matter states it explicitly; "unidentified" or "implied" means the record indicates AI use but does not name a specific product — we do not guess.
Outcome
Fine and Costs Order (monetary penalty: 28000 USD.)
Additional detail
Fine was 3,000 USD, to which the court added 25,000 USD in costs in a subsequent order.
How Citation Safe would have caught this
Citation Safe runs three deterministic layers before a brief is filed: (1) does the citation exist against CourtListener's database of published opinions, (2) if quoted, does that exact language appear in the source, (3) does the cited case actually support the proposition it is cited for. Fabricated case citations fail Layer 1. Fabricated or misattributed quotations fail Layer 2 even when the underlying case is real. Misrepresented holdings — a real case cited for a proposition it does not support — are the target of Layer 3. None of these checks involve asking another language model whether the citation looks right; they are lookups and text-matches against the actual source, which is why a hallucinated citation has to survive a direct lookup against the authoritative source — not another model's opinion — to earn a VERIFIED stamp; our measured false-verify rate is published live at /quality.
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Source: https://www.damiencharlotin.com/documents/1191/Lewis_v._Eagle_Country_USA_14_November_2025.pdf, via Damien Charlotin's public AI Hallucination Cases Database (CC0).