Lucy Worsley is back with a brand new series of Lady Killers. Lucy and her team of all female detectives re-visit the unthinkable crimes, committed by murderesses, more than a hundred years ago.

In this episode, Lucy looks at a case with a difference. It’s true crime meets family history - with a twist. The team receives an email from Lady Killers listener, Charlotte Godfrey, who says she has a Victorian Lady Killer in her family. Charlotte wants to find out more about her Great Great Aunt’s role in The Chertsey Murder.

It’s a tragic tale involving murder and suicide. On 16th May 1894, 18 year-old Amelia Haslett poisons her 9 year-old sister Daisy and then kills herself. What were the circumstances that led to this unimaginable crime?

Lucy brings in Lady Killers’ in-house historian Professor Rosalind Crone to help get to the bottom of this dark family secret.

Ros meets Charlotte at the scene of the crime in Addlestone, Surrey and visits the church where her relatives are buried.

Back in the studio Lucy, Ros and Charlotte are joined by Dr Gwen Adshead who, for many years, was a consultant psychiatrist and psychotherapist at Broadmoor Hospital.

Can they answer Charlotte’s questions – why did Amelia do it and what may have been happening with her mental health. Producer: Julia Hayball Readers: Clare Corbett, Ruth Sillers, Jonathan Keeble and Bill Hope Sound design: Chris Maclean Executive Producer: Kirsty Hunter A StoryHunter production for BBC Radio 4