A woman has been arrested after the death of a 24-year-old Brazilian man, named as John Kennedy Santos Gurjao, on a flight from Lisbon to Dublin on Sunday afternoon.
The man became "agitated and unwell" during the flight and bit a fellow passenger, according to an RTE report.
He was restrained by cabin crew after becoming "extremely violent" in his seat, according to the Irish Mirror.
As the crew battled to help him, the pilot was forced to divert the flight to Cork airport.
According to the Mirror, "the pilot informed controllers of the situation on board and requested clearance to divert and land at the airport after the man started to become extremely violent".
The pilot told flight controllers that there was a passenger "running amok" and that he had "injured one or two passengers", the paper reported.
A passenger told a local radio station: "The noise he was making was like something that I'd never heard before and wouldn't like to hear again ... It was like a deep anguish, that is the best way I can describe it. It was very, very troubled."
After the flight landed, a paramedic crew attempted to save him, but he was pronounced dead on the plane.
Shortly afterwards, a 44-year-old Portuguese woman came forward to say she knew him, the Irish Times reported. She was arrested by gardaí on suspicion of drug trafficking.
According to UTV, the woman was arrested following the discovery of amphetamines on the flight. A Garda spokesperson told the station that she is currently being held at Togher Garda station.
A postmortem on the man's body was carried out at Cork University Hospital on Monday.
RTÉ News reported that a number of packages were recovered from the man's body, and that at "least one of them was ruptured".
The Irish Times reported that a postmortem by Assistant State Pathologist Dr Margot Bolster confirmed the man had ingested around 0.8kg of suspected cocaine in 80 wrapped pellets.
The paper said that toxicology tests are expected to confirm the substance is cocaine and if so, the total quantity of drugs found in Mr Santos Gurjao's system would have an estimated street value of around €56,000 (£41,000).