What was hallucinated

Fabricated: Case Law | Plaintiff cited this case in his opposition brief; the Court confirmed it does not exist and cited it as one of several nonexistent authorities identified by defendant. || Fabricated: Case Law | Plaintiff cited this authority in his opposition brief; the Court confirmed the citation is to a nonexistent decision. || Fabricated: Case Law | Plaintiff included this Third Circuit citation in his brief; the Court determined the opinion does not exist in reporters or databases. || Fabricated: Case Law | Plaintiff cited this D. Minn. opinion (Westlaw cite); the Court independently confirmed the decision cannot be located and is a fabricated citation.

Details

Plaintiff's opposition brief cited numerous nonexistent cases. Defendant identified the fabricated citations in its reply; plaintiff admitted reliance on an AI-based drafting tool and apologized. The court confirmed several cited cases do not exist but declined to pursue Rule 11 sanctions, finding apology, mitigation, and proportionality concerns.

Sanction teardown · D. Minnesota, USA · 2025-11-07

James Andrew Grimmer v. Citibank, N.A.

What happened

In D. Minnesota, 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:

Fabricated (Case Law)

Plaintiff cited this case in his opposition brief; the Court confirmed it does not exist and cited it as one of several nonexistent authorities identified by defendant.
Fabricated (Case Law)

Plaintiff cited this authority in his opposition brief; the Court confirmed the citation is to a nonexistent decision.
Fabricated (Case Law)

Plaintiff included this Third Circuit citation in his brief; the Court determined the opinion does not exist in reporters or databases.
Fabricated (Case Law)

Plaintiff cited this D. Minn. opinion (Westlaw cite); the Court independently confirmed the decision cannot be located and is a fabricated citation.

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

Complaint dismissed with prejudice

Additional detail

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/993/Grimmer_v._Citibank_USA_7_November_2025.pdf, via Damien Charlotin's public AI Hallucination Cases Database (CC0).

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