The Defence Forces, National Bureau of Criminal Investigation, and Garda Technical Bureau have all been enlisted in the search, which began on Monday morning.

The families have been offered assurances that investigators are confident of making progress this time around.

Fr Willie Purcell said while there had been numerous searches over the years, the Dullard family, like the family of Deirdre Jacobs, never lost hope, “because even the smallest piece of information keeps them going.” 

Fr Purcell said he has humbled every time he spoke with Jo Jo’s sister Kathleen and the rest of the family because of "their strength and their courage and their faith in keeping the story of Jo Jo alive". 

“Somebody out there who has information, somebody who has passed on even the smallest amount of information, they are the people who are taking Jo Jo home.

"The information that's given, even the smallest amount of information, people sometimes think, well, that's irrelevant, and that doesn't matter after 30 years, and maybe I've got it wrong, and maybe I picked up something in a different way," he told RTÉ radio’s Today with David McCullagh.

“But the smallest piece of information, it's like a jigsaw puzzle or a tapestry. A piece of thread or a piece of the jigsaw puzzle will bring the whole story together and will bring Jo Jo home.”

When asked what would it mean to the Dullard family to bring Jo Jo home, Fr Purcell said it would be to "have a place to go where now her family knows she's safe".

He added the new search which commenced this week was giving the family a renewed sense of the possibility that this will bring closure.

“And for them, that's why they never lose hope, because if you lose hope, you lose everything. If you lose hope, you lose the person. So again, talking to Kathleen yesterday, and Kathleen very beautifully said, you know, by keeping this hope alive, we're keeping Jo Jo alive in our hearts. And by never losing sight of Jo Jo, and by constantly hoping that Jo Jo will come back, then she's not lost. She's not missing," he said.