Killer Michael Stone was married in Maghaberry prison earlier this week.
The 61-year-old, who launched a one-man gun and grenade attack on an IRA funeral in 1998 in which three people were murdered, tied the knot on Monday.
A prison source said: “The wedding definitely took place and we could not believe it.”
It has been reported that around 12 guests attended the ceremony.
And afterwards guests enjoyed a small buffet of sandwiches and traybakes.
Stone had been released on licence in 2000 as part of the Good Friday Agreement.
But he was returned to prison in 2006 for trying to kill Gerry Adams and Martin McGuinness at Stormont.
Soon after being jailed he told the News Letter he had been carrying out an act of “performance art”.
In 1984 Stone gunned down Catholic milkman Patrick Brady in South Belfast and a year later shot dead joiner Kevin McPolin in Lisburn. He also murdered bread man Dermot Hackett in 1987.