Is Lucy Letby a psychopath – and would she have killed if not?

As Letby’s lawyers claim an expert witness at the trial, Dr Dewi Evans, has changed his mind on key evidence, a new book has been released that explores how a nurse could go from an ordinary young woman to the most prolific child killer of the modern era. Here authors Jonathan Coffey and Judith Moritz reveal what they discovered about her state of mind...