The garda watchdog is examining the circumstances surrounding the death of a man after an incident at the Midland Regional Hospital in Mullingar.
It is understood gardaí arrested the man after being called to the hospital's emergency department on Saturday evening.
However, the 40-year-old later collapsed at home and died after being released from garda custody.
The incident has been referred to GSOC, who say a post-mortem will be carried out this morning.
A statement from gardaí read: "Gardaí at Mullingar Co Westmeath have referred the death of a 40-year-old man to the Garda Síochána Ombudsman Commission.
"The man who was taken from his home by ambulance to the Regional Hospital in Mullingar and pronounced dead at the Hospital on Saturday 23 March 2019 had earlier in the evening an interaction with gardaí at a location in Mullingar.
"As this is now a Garda Síochána Ombudsman investigation we will be making no further comment."
A spokesperson from GSOC added: "A Garda superintendent made a referral to GSOC on Saturday night following the death of a man who had had an interaction with gardaí a short time before his death.
"The incident was referred under section 102 of the Garda Síochána Act 2005.
"GSOC investigators went to Mullingar, and the matter is under examination."