The three siblings who died in a violent incident in Dublin have been named as Lisa Cash, 18, and her younger brother and sister, eight-year-old twins Christy and Chelsea Cawley.
A man arrested following the deaths remains in custody, police in Ireland said.
Officers were called to the property in the Rossfield estate in Tallaght at about 12.30am on Sunday.
Lisa, Christy and Chelsea were taken by ambulance to Children’s Health Ireland (CHI) in Crumlin, but all three were later pronounced dead.
Their mother, a woman in her 40s, has been released from hospital and is currently being supported by her family.
The victims’ 14-year-old brother remains in Tallaght University Hospital with serious but non-life threatening injuries.
The scene remains sealed off for a forensic examination by the Garda Technical Bureau.
Post mortems will take place on Sunday and Monday by state pathologist Dr Sally Anne Collis.
A man, aged in his early 20s and arrested at the scene, continues to be questioned at Tallaght Garda Station.
The Garda Armed Support Unit used ‘less-than-lethal’ devices to arrest the man.
Gardai said everyone involved is believed to have been known to each other and officers are not looking for anyone else in connection with the incident.
Gardai in Tallaght have established an incident room and the circumstances are being investigated under the direction of a senior investigating officer.
Officers described it as a violent, challenging and traumatic incident which was responded to by uniform unarmed Garda first responders from Tallaght District, supported by uniform members and armed detectives and specialist armed support unit members.
An Garda Siochna also said it has put in place welfare support for all officers who attended the incident.
Fianna Fail councillor Charlie O’Connor, who was at the scene on Sunday morning, said there is widespread shock in the community.
“I don’t know how to describe it. I was getting calls from early morning with people bringing it to my attention,” Mr O’Connor said.
“There is deep shock, people are really, really upset, any event like this would cause shock but the fact that it involves children, it’s a really shocking event for this community, and indeed for the wider Tallaght community and elsewhere. This will affect many, many people.
“I was talking to the gardai and they told me that their colleagues who were on last night were all deeply shocked.
“It is terrible. We have to think of the family, think of their neighbours, think of the wider community.
“Attempts are being made to support the local community and the local Brookfield Youth and Community Centre has just confirmed to me that they’re opening up now for the rest of the day.
“People are welcome to come and grieve and have a cup of tea and talk about their grief.
“I really find it shocking to think three children of that age are no longer with us and won’t be going to school in the morning.”
A large garda presence remains in the area while a full forensic examination of the scene is under way.
The upstairs windows of the property were open and smashed while blood stains could be seen on the window frames.
A smashed downstairs window also remained open while forensic officers examined the front garden.
The killing of three young family members is a tragedy so awful and heartbreaking it is difficult to comprehend
My thoughts are with the family and the local community as they deal with this unimaginable crime
Gardaí and other services are supporting them at this difficult time
— Helen McEntee TD (@HMcEntee) September 4, 2022
A black car outside the property was also a focal point of the investigation.
Forensic officers removed a number of items from the scene, including a shoe, small bag and black coat which were placed in forensic bags.
Flowers have also been left at the scene. One floral tribute said: “Fly high little angels. Our hearts are broken for you all.”
The streets surrounding the property remained busy with children playing nearby.
Minister for Justice Helen McEntee said: “The killing of three young family members is a tragedy, so awful and heart-breaking. It is difficult to comprehend.
“My thoughts are with the family and the local community as they deal with this unimaginable crime.
“Gardai and other services are supporting them at this difficult time.”
Dermot Richardson, Sinn Fein councillor for the Tallaght area, called for welfare support to be put in place for the family, local community and schoolchildren.
He also called for people to stop sharing video footage of the incident on WhatsApp and social media sites.
“There are videos being shared on WhatsApp. I would ask people not to share it out of respect for the family and the local community as well,” he added.
“If you have footage, please pass on to the gardai.”