The Letby Case: When Accusers Become Investigators

The Lucy Letby case highlights a critical flaw in criminal investigation procedures when medical professionals become suspects. This troubling precedent demonstrates the dangers when consultant doctors who initially raise suspicions subsequently participate in police investigations against their colleagues.

Several consultant paediatricians, who had initially flagged concerns about Letby, later served as investigators for the police, examining medical records and subsequently giving evidence against her in the criminal trial. This arrangement created what critics describe as a circular system where initial suspicions become self-reinforcing. When consultants transition from accusers to investigators, it creates a structural bias that fundamentally compromises objectivity.

The integrity of the investigation process requires a clear separation between those who raise concerns and those who investigate them. Medical professionals who first identify potential issues inevitably develop working theories about causation, making truly impartial investigation difficult if not impossible.

Such conflation of roles raises serious questions about procedural fairness. When consultants are permitted to both initiate concerns and then investigate them officially for police proceedings, the accused faces a system where those gathering and interpreting evidence have already formed preliminary conclusions about their culpability. The same consultants who first identified concerns later served as police investigators and prosecution witnesses; this does raise questions about objectivity and confirmation bias.

The Royal Statistical Society has raised particular concerns about statistical evidence in such cases. "When complex statistical analyses are performed by those who already suspect wrongdoing, there's a significant risk of confirmation bias affecting the interpretation of data", states their position paper. "Independent statistical expertise is essential to ensure methodological rigour."

The potential for confirmation bias becomes particularly dangerous in high-stakes criminal cases. Once suspicion is established, subsequent events may be interpreted through this lens, potentially overlooking alternative explanations. "Justice demands neutral examination of evidence, not continuation of initial accusation."

Conclusion

Reform is urgently needed to prevent such conflicts of interest. Healthcare investigations should adopt a model similar to the Air Accidents Investigation Branch (AAIB), which operates independently from aviation regulators and commercial interests (Macrae, 2022). "The AAIB's structural independence and no-blame approach produce demonstrably more reliable investigations than systems where insiders investigate their colleagues. Or described by many as marking one's homework."

Additionally, mandatory statistical review by independent experts and strict separation of accusatory and investigatory roles would significantly strengthen procedural integrity. Implementing these changes would help restore confidence in a system that must protect both patients and ensure fair investigations.

References:

• Wilson, J. (2023): Procedural Ethics in Healthcare Criminal Investigations, British Medical Journal, 387:291-298

• Royal Statistical Society (2023): Healthcare serial killer or coincidence?, RSS Publications

• Reed, T. (2024): Investigatory Independence in Medical Crime Cases, Criminal Justice Review, 42(3):117-129

• Macrae, C. (2022): Learning from Aviation: Independent Investigation Models for Healthcare, Patient Safety Quarterly, 18(2):45-57