POLICE in Omagh have appealed to people who were socialising in the Co Tyrone town in the early hours of New Year's Eve for help in tracking down those who attacked Jason McGovern.
The 19 year old from Co Monaghan died after being set upon twice on a night out with friends in Omagh last Sunday.
He was found dead in a friend's house the day after the attack. He had made his way back there after the incident.
Five men and a teenager have been charged with affray in connection with the incident, which happened at around 2am on New Year's Eve on John Street and Kevlin Road.
One week on from the attack, Detective Chief Inspector Richard Harkness, from the PSNI's Serious Crime Branch, said the assistance of local people will be vital in bringing those responsible for Jason's death before the courts.
"There were a large number of people socialising in the area at the time of the assault and also a number of motorists in the area of John Street and Kevlin Road," he said.
Mr McGovern travelled to Omagh with a group of friends but became separated.
He was punched outside a nightclub after being involved in a verbal exchange with a group of men.
He later made his way to the Border village of Emyvale, Co Monaghan, where he had been staying with friends and was found dead at midday on New Year's Eve.
Meanwhile, four men and a youth have appeared in court on charges arising out of the police inquiry.
The men, all aged between 18 and 21 and from Omagh, are accused of unlawfully fighting causing affray in the early hours of December 31.
A 17-year-old also faces a charge of affray. The men were released on bail.
One of the men, 18-year-old Aaron Bradley of Waterworks Road, faces a further charge of assault occasioning actual bodily harm.
Aaron Davis (19), of Beattie Villas, Mark Donnelly (21), of Greencastle Road, and 21-year-old James O'Brien, of Rylagh Road, appeared alongside Mr Bradley at Omagh Magistrate's Court on Saturday.
A detective police constable described to the court how Mr McGovern was "punched", "dragged across the ground" and assaulted again after trying to break up a "fracas".
After being "rescued", the 19 year old made his way up Kelvin Road when he was pursued.
He was punched to the ground and remained unconscious for a small period before being helped into a taxi by a passer-by.
A post-mortem report stated that the teenager's death had been due to a head injury.