Doctor U initially misinterpreted Letby's inquiries about the infants as anxiety, later realizing she was concerned about being implicated in the deaths.

The Thirlwall Inquiry is currently examining Letby's actions and the circumstances surrounding her crimes, with findings expected by late autumn 2025.

Letby was ultimately convicted of murdering seven infants and attempting to murder seven others, receiving 15 whole-life orders.

The ongoing public inquiry, led by Lady Justice Thirlwall, aims to uncover how Letby was able to commit her crimes undetected.

Lucy Letby, the UK's most-prolific child serial killer, was removed from the neonatal unit at the Countess of Chester Hospital in July 2016 due to concerns about her harming infants following a series of unexplained deaths.

By September 2016, junior doctors at the hospital had begun referring to Letby as 'nurse death' due to her involvement in the deaths of several infants.

Concerns about Letby's behavior escalated, leading to police involvement in May 2017, although she continued to work at the hospital until her arrest in July 2018.

The inquiry revealed that Cheshire Police began investigating increased mortality rates at the hospital in May 2017, which coincided with Letby's continued presence on the unit.

Despite Letby's claims of innocence, staff concerns persisted, resulting in her return to the unit being postponed until police were involved.

Dr. Jim McCormack testified that he was ordered to apologize to Letby for accusing her of murder two years before her crimes were revealed.

Doctor U exchanged over 1,300 messages with Letby during a critical period, providing her with support and information, which he later regretted.

Letby used lethal methods, including injecting air into the bloodstream of one infant and into the stomach of another, leading to their deaths.