A 29-year-old woman remains under arrest on suspicion of the murder of a baby boy at a house in north Belfast.
The boy’s young sister is in intensive care after she was injured in the same stabbing incident at Brompton Park in the Ardoyne area on Tuesday evening.
It is understood the children’s father was in England when the attack happened and he has travelled back to Northern Ireland.
A post-mortem examination on the boy is due to take place on Thursday.
MP for the area John Finucane said the local community had been left stunned by what is understood to have been a domestic stabbing.
Detective Chief Inspector Millar from the Police Service of Northern Ireland’s major investigation team said: “Police were called to the house shortly after 8pm and discovered the injured baby and another injured child in the house.
“Despite the efforts of the emergency services the baby was sadly pronounced dead at the scene.
“The other young child was taken to hospital and remains in intensive care.
“A 29-year-old woman who was also in the house has been arrested on suspicion of murder and attempted murder and remains in custody at this time.
“Our thoughts are with the baby’s family, who are being supported by family liaison officers.”
“A post-mortem is expected to take place tomorrow.”
Sinn Fein MP Mr Finucane visited the scene earlier on Wednesday.
He said: “It was a very tragic situation which unfolded here in Ardoyne last night.
“It is my understanding that first responders entered a house, they found two young children very seriously injured and despite their best efforts one child died at the scene.
“Another child has been taken to hospital and is currently in a critical condition.
“Our hopes and prayers are that that child will pull through and make a full recovery.
“Everybody in the community, their thoughts are with the families that are directly affected by this.
“It is a tragic situation compounded by the fact that we are dealing with somebody who has died at such a young age.
“It is incredibly difficult and will obviously leave a mark on those who are most impacted by it, and all we can do is rally round those who need support at this time.
“This has been hugely impactful.
“There were neighbours who assisted and some people who would have witnessed scenes that they shouldn’t have to witness.
“Ardoyne is a very proud community, it is a resilient community also, and I have no doubt whatsoever that they will rally around each other at this very difficult time, they will provide help and assistance for those who need it.
“I would also just stress just for people to exercise caution and sensitivity in regards to what they would post or share on social media – there is a live murder investigation and people need to be respectful of that process as well.”
People Before Profit councillor Fiona Ferguson said the news was “truly devastating”.
“A wave of shock began in Brompton Park last night and spread out across north Belfast,” she said.
“After something so shocking, community solidarity, community support, rallying around each other is going to be absolutely paramount.”