Coroner Dr Fiona Wilcox says despite a police inquiry, involving counter terrorism and an inquest, most questions about Gareth Williams' death remain unanswered.
She says: "It is my view that it's unlikely this death will ever be fully explained."
Whatever the coroner's verdict today at the inquest into the death of MI6 spy Gareth Williams, many questions will remain unanswered.
Last day of the inquest into the death of Gareth Williams
Experts can't rule out the possibility that the MI6 spy found dead in a bag, locked himself in unaided, before dying.