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Cartagena v. Dixon, Blackburn, and T.A. Blackburn Law (1)

Court
S.D. New York
Jurisdiction
USA
Decided
2026-03-10
AI tool
Protégé (LexisNexis)
Outcome
Bar Referral
Monetary penalty
None reported

What was hallucinated

Fabricated: Case Law | Brief filed by defendant's counsel contained multiple non-existent case citations and misstatements of law; court found pervasive 'hallucinated' cases and noted counsel attributed errors to use of 'Protégé' AI.

Details

Bar referral ordered in a subsequent Order.

Sanction teardown · S.D. New York, USA · 2026-03-10

Cartagena v. Dixon, Blackburn, and T.A. Blackburn Law (1)

What happened

In S.D. New York, USA, a filing relied on Protégé (LexisNexis) to help draft legal argument. The court identified the following problems with the citations in that filing:

  • Fabricated (Case Law)
    Brief filed by defendant's counsel contained multiple non-existent case citations and misstatements of law; court found pervasive 'hallucinated' cases and noted counsel attributed errors to use of 'Protégé' AI.

Which AI tool

Protégé (LexisNexis). 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

Bar Referral

Additional detail

Bar referral ordered 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.

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

Source: https://www.damiencharlotin.com/documents/1665/Cartagena_v._Dixon_USA_10_March_2026.pdf, via Damien Charlotin's public AI Hallucination Cases Database (CC0).

Source: https://www.damiencharlotin.com/documents/1665/Cartagena_v._Dixon_USA_10_March_2026.pdf

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