The level of inhumanity behind the arson attack which killed a four-year-old boy and his grand-aunt in Offaly at the weekend is difficult to comprehend, the Taoiseach has said.
Tadhg Farrell and 60-year-old Mary Holt were killed in the blaze which occurred at a terraced house in Castleview Park in Edenderry on Saturday evening.
Speaking at Government Buildings, the Taoiseach described the attack as "savage" and "callous".
Micheál Martin said no effort will be spared by An Garda Síochána and the State to bring those responsible to justice.
He said the use of accelerants in such attacks is becoming more common, adding: "We are determined to wipe it out and to make sure that we can stop this."
Mr Martin said that "it's a savage form of criminal activity, which is reckless and is leading to the deaths of innocent people".
Gardaí are working to identify suspects for the attack, in which another woman, aged in her 50s, was also seriously injured.
She is being treated at the Midland Regional Hospital in Tullamore.
Gardaí described the incident as a "callous, reckless and murderous attack on a family home".
One line of investigation is that the attack may have been carried out by an organised criminal gang involved in the drugs trade in the Midlands.
However, Ms Holt and Tadhg were innocent victims and it is understood the house may have been targeted in a case of drug debt intimidation.
It is believed that a petrol bomb was thrown in the front window of the house sometime before 8pm on Saturday.
The Minister for Justice called on recreational drug users to reflect on the link between drug use and the deaths of Ms Holt and Tadgh.
Speaking in Brussels, Jim O'Callaghan said the deaths emphasised the general danger to the public from drugs activity.
"We all need to face up to our own responsibilities. People taking recreational drugs need to recognise it's not recreation," he said.
"It's imposing very significant violence on many people in our country, and I would ask them and urge them to stop taking recreational drugs."
Minister O'Callaghan said he condemned the attack in the strongest possible terms, adding that the level of violence used "clearly indicates" that it was murder.
He said that while it has not been confirmed that the attack may be associated with the drugs trade, if that does turn out to be the case, it "underlines how innocent people, such as the people injured and killed, can be caught up in the drugs trade".
The minister said gardaí would pursue those involved relentlessly and they would be brought to justice.
"The gardaí have very strong legislative mechanisms available to them. If they required more, I'd give them," he said.
"But my own view is that there are sufficient laws in place to ensure that we can pursue the dangerous criminals who are responsible for this heinous act."
Minister O'Callaghan extended his condolences to the families involved and wished the woman in hospital a speedy recovery.
Post-mortem examinations on the bodies of Tadhg and Ms Holt were carried out by Assistant State Pathologist Dr Margot Bolster yesterday afternoon.
The scene remains sealed off today as further technical and forensic examinations continue.
Castleview Park is a long established housing estate close to the town.
Local Fianna Fáil Councillor Claire Murray said it was a "dark day" for Edenderry and there is an "awful sense of heaviness" in the area.
Speaking on RTÉ's News at One, she said many people knew Ms Holt and Tadhg.
"Mary worked in a local nursing home and I believe she was one of the longest serving members in the nursing home. She gave an awful lot of time and dedication and care to so many people in Edenderry," she said.
"And then you look at poor Tadhg. Only a few days ago he was probably looking forward to the Toy Show, to Christmas, to Santa coming. All the things that any four-year-old would be looking forward to. His future was robbed from him and people are just so raw," added Ms Murray.
Independent Ireland Councillor Fergus McDonnell called on local people to support gardaí and come forward with any information about the attack.
Speaking on RTÉ's Morning Ireland, he said: "I'd ask people to support the gardaí with any information they have or may have, whether it be dash cam footage or word of mouth information, to pass that on to the gardaí and to make sure that these people are brought to justice and face the full rigours of the law."
Cllr McDonnell said people are very cautious and nervous following the attack.
Drugs are the scourge of society worldwide, he said, and there are drugs in every town and village throughout Ireland.
