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Ontario Court Catches Fabricated Case Law in a Filed Factum

April 25, 2025
Curated by Team Raidu · Reviewed by Shiva Ganesh
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What happened

In April 2025, an Ontario Superior Court judge reviewing a family law matter found something that should not have been there: a legal factum with citations to cases that either did not exist or had nothing to do with the points they were meant to support. The case, Ko v. Li (2025 ONSC 2766), was not a high-profile dispute, but the problem Justice FL Myers identified in the applicant's filed materials had implications well beyond this particular motion.

Justice Myers reviewed the factum submitted by counsel for the applicant and identified multiple case citations that were inaccurate or entirely fabricated. Some of the cited decisions were irrelevant to the legal arguments they were attached to. Others misrepresented what the case had actually held. Several did not exist at all. Myers questioned, directly in the ruling, whether generative AI had been used to draft the document, noting that the pattern of errors was consistent with a tool that produces plausible-sounding citations without verifying whether those cases are real.

The court responded with a show-cause order requiring the lawyer to explain why she should not be held in contempt. The ruling grounded this in two existing professional obligations: the duty of accuracy owed to the court, and the duty of technological competence that Canadian lawyers carry when adopting new tools in practice. Neither duty was novel. Both were violated, or at least that was the question Myers put to counsel.

Ko v. Li landed at a moment when courts had been fielding questions about AI-assisted legal drafting for several years. Myers did not hedge the concern. The show-cause order treated the problem as one requiring a formal legal answer rather than a quiet correction, which is a different kind of signal than a judicial footnote asking counsel to be more careful next time. The distinction matters because a contempt proceeding carries consequences for the lawyer personally, not just for the filing.

The deeper issue is not that a lawyer used a drafting tool but that nothing in the submission process required her to verify what the tool produced. Every case citation in a court filing is a factual claim, and almost no standard legal workflow creates a provable record of what a system generated versus what a human confirmed as accurate. That gap, between producing a document and certifying its contents are real, is where the contempt question lives, and it will keep reappearing until verification is something the process demands rather than something the practitioner is simply expected to perform.

Reported impact

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Harm type
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Financial impact
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Regulatory action
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Classification

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Relevant governance controls

Governance control mapping is not available for this record.

  • No controls mappedNot publicly disclosed

Control mapping is analytical. It does not state that any control would have prevented the incident.

Sources and evidence

This record was researched and written by the Index. The event is also catalogued in the following database, which is listed for cross-reference.

AI Incident Database
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Ontario Court Catches Fabricated Case Law in a Filed Factum
2025-04-25