The death of a teenager on New Year's Eve is being treated as murder, police have said.
Jason McGovern, 19, from Tydavnet, Co Monaghan, died after being assaulted during a night out in Omagh, Co Tyrone, on Sunday.
The detective leading the murder hunt said post-mortem examination results revealed he died from a head injury.
Mr McGovern, who cared for his mother who suffers from multiple sclerosis, was injured after being punched at a bar on John Street in Omagh and then hit again two hours' later outside a nightclub on the Kevlin Road.
It is understood Mr McGovern may have been trying to break up a fight. He managed to make his way home to the border village of Emyvale, Co Monaghan, where he was believed to have been staying with a friend.
His body was found just after midday on New Year's Eve.
The murder investigation is being led by the PSNI and supported by Gardai.
Detective Chief Inspector Richard Harkness appealed for taxi drivers and motorists at the Weigh Inn car park, Omagh, to come forward.
The detective is especially keen to speak to two middle-aged men who helped Jason into his taxi with his friend after the assault. The men are not linked to the assault.
Police are also trawling through CCTV footage from the car park and Omagh town centre. The PSNI are keen to speak to a man of stocky build with ginger or blond-coloured hair as part of their inquiries.