The man and woman are being held under anti-gang laws.
Gardai are still questioning two people about the murders of a couple and two children in Waterford.
The man and woman are being held under anti-gang laws.
Meanwhile a Dail protest is being planned by families affected by drugs-debt intimidation.
Gardai investigating the murders of Philip and Kim English and two of their sons in an arson attack this week, made their first arrests yesterday.
A man in his 20's and a woman in her 30's were detained under anti-gang laws - meaning Gardai have a full 7 days to question them.
Two other children injured in the firebombing on Tuesday morning are still fighting for life in hospital -
The investigation has been described by investigators as 'active and intensive' and is understood to centre on drug-debt intimidation.
The Irish Examiner reports today that families impacted by the issue are planning a Dail protest to highlight their anger and frustration.

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