A man and a woman are still being questioned following their arrest in connection with an arson attack in Waterford that killed four members of the same family.
Philip and Kim English and their sons Callum, 12, and Jayden, nine, died in the attack on their home on Tuesday.
Two other children remain in critical condition in hospital.
A man in his 20s and a woman in her 30s were arrested on Thursday suspected of facilitating the activities of an organised crime group and remain in custody.
Gardaí have carried out several searches and seized a number of items in the investigation, Garda Commissioner Justin Kelly said on Friday.
He said that he expects more arrests in the murder investigation and that An Garda Síochána has “given every resource” to investigating the deaths.
The funerals of the four victims will take place in Waterford on Monday.
