What was hallucinated

Fabricated: Case Law | Brief contained multiple fictitious case citations generated by AI (cases that did not exist). Court found citations were fabricated and not verifiable. || Misrepresented: Case Law | Brief cited existent cases that did not stand for the propositions for which they were cited (misrepresentation of precedent). || False Quotes: Case Law | Brief included misquoted passages and quotations attributed to cases that were inaccurate.

Sanction teardown · CA Maryland, USA · 2025-10-29

Mezu v. Mezu

What happened

In CA Maryland, USA, a filing relied on ChatGPT to help draft legal argument. The court identified the following problems with the citations in that filing:

Fabricated (Case Law)

Brief contained multiple fictitious case citations generated by AI (cases that did not exist). Court found citations were fabricated and not verifiable.
Misrepresented (Case Law)

Brief cited existent cases that did not stand for the propositions for which they were cited (misrepresentation of precedent).
False Quotes (Case Law)

Brief included misquoted passages and quotations attributed to cases that were inaccurate.

Which AI tool

ChatGPT. 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

Referral to Attorney Grievance Commission

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.

Check a brief before you file it → · See our live false-verify rate

Source: https://www.damiencharlotin.com/documents/959/Mezu_v._Mezu_USA_29_October_2025.PDF, via Damien Charlotin's public AI Hallucination Cases Database (CC0).

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