Four people are now being questioned about the murders of a young boy and a woman in Co. Offaly.
Tadgh Farrell and Mary Holt were killed in a firebomb attack in Edenderry last year.
It was the night after the Late Late Toy Show last December 6th when a petrol bomb was thrown into the downstairs of the house in Castleview Park in Edenderry.
The bodies of 4 year old Tadgh and his 60 year old grand-aunt were discovered in the front room of the house when emergency services were called.
Tadgh's grandmother who was also into the house at the time suffered serious injuries but survived.
Yesterday Gardai confirmed they'd arrested two men in their 20's and another in his 30's as part of the murder inquiry.
Last night a teenage boy was also detained.
All four are being questioned at Garda stations in the midlands
