of the trial about further investigations into lucy letby�*s nursing career, notjust at the countess of chester hospital but at liverpool women'sg her time as a nurse. an investigation by bbc news and bbc panorama has revealed that the infant mortality rate on the neonatal unit where lucy letby worked was five times what it should have been, five times higher than the average. there were more deaths on the unit than she has been convicted of, and she was present for all of them. there were also concerns that issues were raised, potential problems about lucy letby, potential problems about lucy letby, potential concerns about her behaviour and the skill of her nursing, the fact that these things were happening while she was on duty had been right, and concerns that they were not taken seriously by senior management. our social affairs correspondent michael buchanan has this exclusive report. this is the story of an nhs trust that didn't properly investigate why 13 babies died in a one—year period. instead, it turned against the very people who wanted the police to examine the deaths. there is only one serial killer of babies tha

s last year on the neonatal unit. she was on duty for every one of them. the police investigation is going wider still. two babies died while lucy letby was training at liverpool women's hospitalentire footprint of lucy letby's career, all the way through lucy's placements at chester and at the liverpool women's hospital. and could that result in, in further charges down the line? possibly. we have informed a number of parents already that we're investigating their child, and they're being supported. the countess of chester hospital is under new management. the unit no longer cares for such sick babies, and there's only been one death in seven years. can expectant mothers coming into the unit have confidence? i think those parents can expect as high a level of care on our unit than any other unit in the country, really. it's upsetting, this. mm. we've got through a particularly hard time, and... i think we owe it to the families, for them to know that the staff care. lucy letby now faces years in prison for harming babies in her care. but why did she do it? what turned a likeable, fun—loving nurse into a serial killer? i don't think we know why, why lucy letby has done this. a