The men were detained following a series of searches in Dublin this morning.
Gardai are continuing to question three men in connection with the murder of a 17 year old youth in Drogheda in January last year
They were arrested following searches of a number of properties across the capital this morning
The men, who are in their 20s 40s and 50s, are being held at a number of Dublin Garda stations under Section 50 of the Criminal Justice Act under which they can be held for up to seven days before they must be be charged or released.
Legislation that would allow the naming of child victims of murder or manslaughter are expected to come into force this week
The restrictions had stopped grieving parents from speaking publicly about their child when they were victims of homicide.