A man in his mid twenties — who reportedly bit a passenger on a flight from Lisbon to Dublin Sunday afternoon — died after becoming agitated, Irish police confirmed to Mashable on Monday.

The 25-year-old man fell unconscious after the incident on the Aer Lingus flight — prompting the captain to declare a medical emergency. The flight was diverted to Cork where it landed at around 5:40 p.m. The man was pronounced dead at the airport.

Some 170 passengers and crew making the Flight EI 485 journey were interviewed by local police and later transported to Dublin by bus.

Police told Mashable another passenger was taken to Cork University Hospital with a bite mark, and that "it does appear" that the dead man bit someone else. They said in a statement:

Gardaí are investigating the sudden death of a man aged 25 on a flight from Lisbon to Dublin. The flight was diverted to Cork airport when the man on board became agitated. He was attended to by a doctor and nurse who were on the flight but was pronounced dead at the airport at 6.40pm. The body of the man was taken to Cork University Hospital where a PM will be held this afternoon. A passenger on the plane received a hand injury during the incident and was treated at CUH.

A witness told the Irish Times she saw the man, who she said was Brazilian, get up to go to the toilet halfway through the flight. The woman, who asked not to be named, said he looked "really unwell" and climbed over seats to pass cabin crew and reach the rear toilet. A call went out from the captain for any doctors or nurses on board, and it became clear the man had collapsed outside the bathroom, she said.

“At that stage they started to perform CPR,” she said. “You could hear him start to... well, screaming isn’t quite the word. It was a guttural noise, like a wounded animal." A Portuguese man went down to help, the woman said, and he was the one who was bitten.

“The young Brazilian man was having a seizure and they were all restraining him. It wasn’t a random attack. He bit him during the seizure,” she said.

A postmortem is due on the man on Monday afternoon.

Aer Lingus flight #EI485 from Lisbon to Dublin diverted to Cork after a man died on board http://t.co/C8pPNnmxl8 pic.twitter.com/NoQkJDszW3 — Flightradar24 (@flightradar24) October 19, 2015

A Portuguese woman on the flight was also arrested at the scene under Section 2 of the Drug Trafficking Act, Irish police told Mashable. However, no link has been established between the two people and they're treating it as a separate incident.

During the course of the investigation into this incident Gardaí discovered what they believe to be 1.8kg of amphetamines in the luggage of a woman in her 40s who was on the same flight. The woman, believed to be a Portuguese national was arrested at 11pm and is detained at Togher Garda Station under Section 2 Drug Trafficking Act.

Mashable has reached out to Aer Lingus for comment.