A man has admitted murdering his three-week-old son and attempting to murder the child's mother.
Andrei Stefan and his mother Andreea Stefan were found with stab wounds at a property on Portland Close, Wallsend, North Tyneside, on 2 October.
They were taken to hospital, but Andrei died four days later, while 21-year-old Andreea survived.
Denis Erdinch Beytula, 27, pleaded guilty to both charges at Newcastle Crown Court.
Beytula, of Portland Close, Wallsend, was remanded in custody by Judge Penny Moreland ahead of his sentencing on 19 December.
Emergency services were called to the property at about 02:15 BST on 2 October, where they found both Ms Stefan and baby Andrei with critical injuries.
As the mother's condition improved in hospital her son's worsened, and he was eventually declared dead.
Det Ch Insp Dave Cole, of Northumbria Police, said it was "impossible to imagine" what the baby's family had gone through in the aftermath of the stabbings.
Police said Beytula stabbed the mother and child after an argument.
Ms Stefan was able to dial 999 before Beytula rang police himself just seconds later to tell them what had happened and he was arrested at the scene.
In a statement after the hearing she said: "I would like to take this opportunity to thank to everyone who came to leave flowers and toys and paid respect to my son.
"I really appreciate it and thanks to everyone for the messages, it's really nice to see how you guys support me and my family during this hard time."
Det Ch Insp Cole said: "Even now it is difficult to comprehend how Denis Beytula could commit these offences.
"His victims were both completely innocent and they were two people he was supposed to love and protect - he betrayed them in the most violent of ways.
"Andreea has been a pillar of strength throughout our investigation and I want to take this opportunity to praise her for her incredible bravery at what continues to be a very difficult time.
"Andreea fought for her life and because of her determination she is alive today to see this man put behind bars, but what happened that day will stay with her for the rest of her life."