Sinn Fein councillors in Limavady have backed a proposal for a judicial inquiry into the 1972 Claudy bombing.
Nine people were killed in the no-warning bomb
Nine people, including a nine-year-old girl, were killed in the explosion at the County Londonderry village. But the bombers were never caught.
At Thursday's council meeting, Sinn Fein Mayor Anne Brolly seconded the proposal by Boyd Douglas of the Unionist Coalition.
Mrs Brolly said she fully supported the motion.
"I felt that what happened in Claudy was a grievous wrong," she said.
"If we can get at the truth and bring succour to the families in Claudy, then I certainly wanted to support the motion and I think it was wholeheartedly and unanimously supported in the council chamber."
In December 2002, the police said a priest was involved in the Claudy bombing.
It also emerged that both the Catholic Church's cardinal at the time, William Conway, and the then Secretary of State, William Whitelaw, met to discuss the matter.
However, a politician who was a junior minister at the Northern Ireland Office at the time of the Claudy bombing said he knew nothing of an alleged cover-up over the involvement of a Catholic priest in the attack