To have custody of a prisoner, a State must hold that person in one of its facilities. A State may have custody of a prisoner over whom another State maintains jurisdiction.

a state of being confined (usually for a short time); "his detention was politically motivated"; "the prisoner is on hold"; "he is in the custody of police"

holding by the police; "the suspect is in custody"

prison (defendant/accused may be "remanded in custody" meaning returned to prison).

Either when someone is under the physical control of the court to make sure s/he goes to court when s/he is supposed to, or when the court sends someone to jail or prison after s/he is found guilty of a crime.

Confinement in a police station, prison or remand centre.

The detention by the police of a person suspected or accused of a crime or offence. Dean of Faculty The elected head of the Faculty of Advocates. The present Dean of Faculty is Andrew Hardie QC