Four men are being questioned by gardai in relation to the murder of two youths at the Canal in Kearneystown, Celbridge, Co Kildare last January.
The men were arrested in Naas and Dublin on Tuesday and are being detained in Naas and Newbridge Garda Stations under Section 30 of the Offences Against the State Act.
A Garda spokesman said that up to 30 people had so far been detained in relation to the murders.