A man in his 40s collapsed and later died when being arrested in Tullamore, Co Offaly, on Monday.
It is understood that the gardaí were called to the scene of a disturbance in the town at around 4pm and when in the course of arresting the man, he took ill.
The Garda Síochána Ombudsman Commission was notified and are conducing an inquiry as is required in all such instances.