In 1986, Diane Sindall leaves work to drive home but never arrives. What happened that night marks the start of a decades long unsolved case.

Through testimony from those who knew her and those who encountered the crime scene, we look at Diane’s final movements, the violent nature of her attack and the growing fear gripping Birkenhead, a town on the Wirral in Merseyside.

As we find out more, troubling questions emerge about how such brutality could occur in a public place unseen and unheard, setting the stage for what would become one of Britain’s most haunting criminal cases.

Presenter: Olivia Graham.

There’s graphic descriptions of violence in this series. For details of help and support in the UK, visit bbc.co.uk/actionline.