Philip Cairns disappeared on the afternoon of October 23 1986 while walking back to school in Rathfarnham.
His family made an appeal on RTE’s Scannal last night for anyone with information to please come forward.
On the day he disappeared Philip left his home in Ballyroan at 13.30 to return to school, Coláiste Éanna.
A large-scale investigation was carried out at the time but no trace of Philip has ever been found.
His disappearance is among the highest-profile cases in the history of the state and last night’s documentary explored the devasting impact on Philip’s family who still don’t not know what happened to him over 30 years later.
Anyone with any information relating to the disappearence of Philip Cairns should contact:
Garda Síochána: 01 666 6500