As police put out a renewed appeal, we question whether long ignored patterns of sexual violence raise the possibility of a serial offender and whether Diane’s killer could have been stopped.

We are also reminded that Diane Sindall’s murder is not just about the past as we visit a vigil for victims of violence against women.

Presenter: Olivia Graham.

Producers: Kate Bissell, Gemma Maull and Olivia Graham.

Sound Design and Music Composition: Phil Channell.

Mixing: Ivan Eastley.

Story Consultants: Neil McCarthy, Jack Kibble-White and Kirsty Williams.

Online Producer: Rachael Smith.

Development was by BBC Audio Scotland and BBC Merseyside.

Executive Editors: Gillian Wheelan and Ben Anderson.

Commissioning Editor: Alistair Miskin.

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

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