The Beast of Birkenhead: 6. Back In Birkenhead

Returning to Birkenhead in the wake of Peter Sullivan’s release, we focus on Diane Sindall and the community still living with her murder.

Peter shares details of his arrest, interviews and alleged police pressure, alongside renewed police enquiries that revisit overlooked witnesses and potential suspects.

As officers collect fresh DNA and old memories resurface, the search begins anew for the man known only as 'Unknown Male One'.

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.