A 48-year-old man has been arrested in connection with a death 17 years ago.
Stephan Hinc, from Riverside, Cardiff, was originally believed to have died at home from natural causes on 28 May, 1993.
But fresh information led to South Wales Police's major crime team opening an investigation.
A man from Penarth, Vale of Glamorgan, has been arrested and is being held in custody at Cardiff Bay police station. Police are appealing for information.
The coroner and surviving family members of Mr Hinc have been made aware of the investigation.
Anyone with information is asked to contact the incident room on 029 20571 583, or 101, or Crimestoppers on 0800 555111.