Those who knew Abraham want further investigation work to take place to try to identify his killer and bring them to justice. Experts say Abraham’s story opens up questions about how suitable the current system is for protecting witnesses.

Presenter and Original Research: Sam Holder
Series Producer and sound design: Anishka Sharma
Story Consultant: Robert Awosusi
Additional Research: Christy Callaway-Gale

Theme music written and performed by Rebekah Reid and Tapp Collective.
Original music compositions by Femi Oriogun-Williams

A Whistledown Production for BBC Radio 4.