A 17-year-old boy remains in hospital in Dublin following a row at a Tusla care unit during which another teenager was stabbed to death.
The post-mortem examination on the victim, who was from Ukraine and also 17, is due to be carried out later.
Two other teenagers were also attacked at the unit, which is at an apartment complex, while a care worker who tried to intervene sustained minor injuries.
Gardaí say they are following a definite line of inquiry in the investigation and have stressed there is no danger to the community.
The 17-year-old sustained non-life-threatening injuries during the row at an emergency residential unit in Grattan Wood in Donaghmede.
Gardaí are waiting to interview him about the fatal stabbing of the Ukrainian teenager at the unit, and attacks on a member of staff and other unaccompanied minors, who are seeking international protection.
Two other teenagers were also attacked but one managed to fight off the assailant.
The teenager who died sustained severe injuries to his head, face and upper body.
The scene at the apartment complex remains sealed for ongoing forensic examination.
Gardaí have said they are not looking for anyone else and describe the incident as self-contained.
Gardaí and the Government are anxious that certain elements, particularly online, do not succeed in weaponising the incident as part of their own anti-migrant agenda.
The Taoiseach, Tánaiste, and Ministers for Justice and Children have all expressed their sympathies, shock and sadness and stated that gardaí must be given the time and space to conduct what is now a murder investigation.
The residential unit is run by a private company on behalf of Tusla and staffed on a 24-hour basis.
It provides care to four unaccompanied minors - separated young people who arrived in Ireland seeking international protection.
Tusla said its immediate priority is the safety and wellbeing of the other young people and staff at the unit.
It also said it is providing additional supports to everyone directly affected and making efforts to contact the families of the four young people who resided at the unit.
