The 72-year-old died within HMP Grampian on 13 August 2024 following a decline in his health.
Mr Duncan was in legal custody and in the care of the state at the time of his death.
The Crown Office and Procurator Fiscal Service is obliged to investigate such deaths, and a Fatal Accident Inquiry is mandatory.
A Preliminary Hearing will be held on 10 June 2026 at Peterhead Sheriff Court.
The purpose of a Fatal Accident Inquiry (FAI) includes determining the cause of death; the circumstances in which the death occurred; and to establish what steps, if any, could have been taken to minimise the risk of future deaths in similar circumstances.
Unlike criminal proceedings, FAIs are inquisitorial in nature, and are used to establish facts rather than to apportion blame.
Procurator Fiscal Andy Shanks for the Crown Office and Procurator Fiscal Service, Scotland’s independent deaths investigation authority, said:
“The Lord Advocate considers that the death of Arthur Duncan occurred whilst he was in legal custody and as such a Fatal Accident Inquiry is mandatory.
“The lodging of the First Notice enables FAI proceedings to commence under the direction of the Sheriff.”
Further information
For more information on Fatal Accident Inquiries see the Crown’s guide.