They carried him through the snow to the grave that has long awaited him in St Patrick's cemetery in Crossmaglen. After 31 years buried in bogland across the border, Gerard Evans was finally home.

Around 300 mourners gathered on a biting cold but sunny day to pay tribute to the 24-year-old unemployed painter-and-decorator who was abducted and murdered by the IRA after leaving a dance in Co Monaghan.

His mother Mary (78) looked exhausted, her eyes swollen from crying, as she followed the hearse into the church.

"Certain people took upon themselves to play God with regard to the life of Gerard Evans," Cardinal Sean Brady told mourners. "They took upon themselves to be judge and jury, executioner and undertaker. What arrogance. What appalling wickedness." Quietly, Mary Evans remembered her eldest son who liked darts and fishing and sometimes took the floor to sing at a session.

After Gerard didn't come home that night in 1979, she refused to belief anything bad had happened. "At first (the) waiting was filled with hope – that hope that Gerry would turn up safe and sound," Cardinal Brady said.

"But as the years rolled by, one kind of hope was replaced by another – the hope that his remains would be found so mourning could begin." Gerard Evans' brother Noel said it was great to have him home but described the day as "bittersweet".

"The pain is still the same whether it happened 31 years ago or seven weeks ago," he said. "We want to thank people for finally coming forward and giving us information." The IRA has always denied disappearing Gerard Evans. These denials have been strongly supported by Gerry Adams and local MP Conor Murphy.

But it was one solitary member of the IRA's South Armagh Brigade who came forward to the Sunday Tribune last year to break the omerta. He gave us a map showing the field in Carrickrobin, Co Louth, where the body lay. He said he was sick of the lies.

He was one of the 12-strong unit who killed Evans, an alleged informer. He put his own life at risk by coming forward.

"If it got out I was speaking to you, I'd be dead," he said. With the IRA man's approval, we passed on the map and other details to the Independent Commission for the Location of Victims' Remains.

The IRA man told the Sunday Tribune he was delighted the body had been found. But he didn't hear the family's words of gratitude, nor attend the funeral. "I'd be a hypocrite to have gone," he said. Sinn Féin MP Conor Murphy was among the mourners.

At least 16 people were disappeared by republicans. Nine bodies have yet to be found.