Gardai say two sisters and a brother died tragically in Tallaght early on Sunday morning.
The incident happened shortly after midnight as officers were called to a house in the Rossfield Estate.
Eight year old twins, a boy and a girl along with an eighteen year old woman died this morning in what gardai are calling a violent incident.
The siblings were rushed to hospital where they were pronounced dead.
A fourteen year old boy was also brought to hospital where he's being treated for non-life threatening injuries. The mother of the children, who was not injured at the scene, was also taken to Crumlin hospital and is currently receiving medical treatment.
Gardai have arrested a man in his 20s in connection with their deaths.
All people involved in the incident are believed to be known to each other. Gardaí said they were not looking for anyone else in relation to the incident.
The scene in Rossfield Estate remains sealed off and a forensic examination will begin later by the Garda Technical Bureau.
