A post mortem examination is being carried out on the body of a 65-year-old man who died following a dispute near his Co Cork home.
John Twomey was in an ambulance with his older brother, Pat, when he died of a suspected heart attack.
He was pronounced dead when he arrived at Cork University Hospital at 6.30pm yesterday evening.
Pat Twomey is described as being in a stable condition.
They were taken to hospital after an alleged dispute involving three men near Rylane.
Gardaí are expected to interview a third man in relation to events yesterday afternoon.
They are investigating allegations that the two elderly bachelor brothers sustained injuries from a wooden implement during a fight with another man in a field near their home outside Coachford.
It is understood that after the fight, the two brothers drove a short distance home, rang the gardaí and the ambulance service.
The field where the alleged incident happened has been cordoned off while the garda investigation continues.
Senior gardaí said the results of the post mortem examination will decide what direction the investigation will take.