Lucy Letby:Unanswered Questions: Former nurse Lucy Letby became one of the UK’s most notorious child killers after she was convicted of harming and murdering babies in her care. The nurse was found guilty by two juries after lengthy trials, but now a growing number of experts are questioning the prosecution's evidence. Reporter Judith Moritz, who has covered the case from the start, investigates the questions that have been raised about Lucy Letby’s conviction.