The investigation of deaths occurring in unnatural, surprising and unclear circumstances is an important area. Death investigation matters for myriad reasons, including: (legal) accountability for risky practices, individuals and institutions; public health and safety; systemic institutional concerns and unaddressed risks; medical care quality; to address community concerns; and for bereaved individuals’ understanding. [---] To support the UK’s compliance with Article 2 of the European Convention on Human Rights (ECHR), which protects the right to life, the Prisons and Probation Ombudsman (PPO) has been investigating prisoner deaths in England and Wales since 2004. [---]