Scores of recovery workers and volunteers from across Ireland will join a major operation in the Strabane area today to find missing man David Colhoun.
Relatives of other missing persons will also join the co-ordinated push to search stretches of the River Mourne and Lough Foyle for the 22-year-old who has been missing since May.
David, who comes from the Donegal border town of Lifford, has not been seen since the early hours of Sunday, May 22.
On the night he vanished, he got out of a police car and ran off in the direction of the River Mourne, which straddles the border and separates the two towns.
Irish rescue charity Searching For The Missing, which operates through Facebook, is behind the fresh search of the area where David was last seen.
Among those taking part will be volunteers from the the Boyne Fishermen, Belfast and Foyle Search and Rescue squads along with groups from Limerick, Waterford, Dublin and Galway.
They will be joined by Shane Doherty, the brother-in-law of six-year-old Donegal girl Mary Boyle who went missing near Ballyshannon in south Donegal in March 1977.
Two sisters of missing Limerick man Shane Moran will also take part in today’s search. The 21-year-old went missing near the River Shannon in January 2009, with searches still ongoing to find his remains.
David’s father Joe has now been looking for his son for 16 weeks.
“I really, really appreciate all the help we have got over the past weeks and I am delighted we are having this big squad here for this weekend,” he said.
“The grieving is passed and we now need closure.
“We want to find him so we can bury him with his mother Josephine, who died on January 7 this year.”
David Colhoun went missing in May after being arrested by the PSNI in Strabane for what was described as minor offences. From Lifford in Co Donegal, the 23-year-old was on a night out when he was detained. He ran off while being transferred between police cars and, according to his father Joe, was last seen on the bridge heading towards Lifford.