Three men have been charged with the murder of an inmate at Christchurch Men's Prison.
44-year-old Benton Parata was assaulted last week and hospitalised with critical injuries. He never regained consciousness and died on Monday.
Those accused with murder are aged 20, 21 and 36. They will appear in the Christchurch District Court next week.
Detective Senior Sergeant Mark Worner says police investigators have been working closely with Corrections staff and the victims family.
10 staff are still working on an ongoing investigation into the incident.
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