Relatives of members of a gang who murdered a young truck driver in Co Armagh were tonight urged to come forward as detectives investigate 1,200 lines of inquiry into the death.
Paul Quinn was lured from his home by several men to an isolated farm a few miles over the Border last October.
They beat the 21-year-old with iron bars and left him for dead. Gardai revealed they have taken 400 witness statements from people in 70 townlands across the South Armagh and North Monaghan Border region.
Superintendent Karl Heller, who is heading up the murder investigation, urged relatives of the gang to come forward.
"These people have families and this was a brutal murder. Clearly this must affect these people in a such a way that you would notice differences, and we would appeal for them to act," he said.
Gardai believe a large number of people were in the outbuildings on the farm at Tullycorra near the village of Oram on the night of the attack.
"We are satisfied that there people in both the South Armagh and North Monaghan, or indeed the greater area, and they are people with key, vital information and these people are still there," Mr Heller said.
Detectives are also trying to trace a white van, either a Toyota Hiace or Nissan Vanette, they believe was used by the gang.
Mr Heller appealed for anyone working in the car, scrap or dismantler business who may have been approached with the van, up to 10 years old, with black bull bars on the front, to come forward.
Detectives believe IRA members were part of the gang which lured Mr Quinn to his death but the murder has not been linked to the terror group's leadership.
Gardai have spent the last three months carrying out door-to-door inquiries across the Border area. With the help of detectives from the Police Service of Northern Ireland they have interviewed hundreds of people in 20 villages in South Armagh and 70 townlands in North Monaghan.
"We have in excess of 400 statements from various people as a consequence of our inquiries and that whole process is ongoing," the Supt said.
"We are as determined as ever to bring the perpetrators of this dreadful crime to justice. "I do believe that there were people who were in the shed and outbuildings on that Saturday night. There was a large number of people present and I would ask these people to come forward."