Gardaí investigating the sudden death of a young Brazilian man on board an Aer Lingus flight have arrested a woman.
The 24-year-old suffered a violent seizure during the flight, which had left Lisbon bound for Dublin.
A woman who was also travelling on the plane has been arrested.
She is believed to be Portuguese but it is not yet clear what her links are to the deceased man.
There are indications that the woman may have been accompanying the man but these reports have yet to be confirmed.
John Leonard from Cork was on the flight and described the scene after the man first appeared to suffer a seizure and then had to be restrained at the back of the plane before collapsing.
"Horrible. I would say a very violent end - to die that way in the back of an aeroplane, it's not right. It was not very pleasant at all," he said.
One man who attempted to restrain the passenger was bitten on the arm.
Mr Leonard told PJ Coogan's Opinion Line on Cork's 96fm two nurses and a doctor tried to resuscitate the man.
The captain of the flight had asked if there were any medics on board.
"After that it got worse I would say, his seizure seemed to get worse. He was actually on the ground shaking violently," Mr Leonard said.
"The noise he was making was like something I have never heard before.
"It's not something you'd hear everyday. It was like deep anguish is the best way I could describe it, very, very troubled. Not screaming in a sense you know if you'd hurt yourself or something, just a very guttural, from deep within him."
The other 167 passengers on flight EI485 were kept on board for two hours after it landed at 5.40pm before being interviewed by gardai and offered bus transfers to Dublin.
Mr Leonard said passengers remained "extraordinarily calm" but were in shock following the incident.
Aer Lingus described the incident as a "medical emergency".
The post-mortem examination is to be carried out in an attempt to establish if the man suffered a seizure or had an underlying medical condition or if there was another reason for his condition.
Authorities have spoken to all passengers on board in relation to the incident.
A post mortem is due to be carried out today at Cork University Hospital.