Officers have completed their investigation into complaints by almost 20 former pupils of a secondary boarding school in Co Cork.
The first complaints were lodged in August last year when gardai were contacted by a former boarder at the school.
The ex-pupils claimed they had been sexually abused at the school in the 1970s, 1980s and early 1990s when it was being run by the order of the Missionaries of the Sacred Heart.
The complaints were filed against four former members of staff, one of whom has since died.
Claims
An investigation was launched by gardai from Cobh and Glanmire with back up from members of the sexual assault unit at the national bureau of criminal investigation in Dublin.
Some of the victims alleged they were subjected to repeated abuse over a lengthy period and, as part of their inquiries, gardai tracked down other former pupils, who the victims said could substantiate their claims.
Last May gardai arrested three elderly suspects for questioning about the allegations. Two of them were detained in Cobh while the third was held in Dublin. All were released subsequently without charge.
Gardai have completed their investigations and a number of files are said to be at an advanced state.
The DPP will determine whether criminal charges should be brought.
In the past, the DPP has ruled against some criminal prosecutions because of the time lapse or because the suspects had since died.