Why teen stabbed his grandad to death
A teenage boy who killed his grandfather for being "creepy" will spend a maximum of 16 years in prison.
Victorian Supreme Court Justice Paul Coghlan on Thursday set a non-parole period of 11 years, for the boy who repeatedly stabbed his grandfather at his home and then walked back to school.
The court heard the child killer had ambitions of joining the army but will instead spend more than a decade behind bars. He cannot be identified for legal reasons.
Justice Coghlan said the boy was 16 at the time of the offence.
In August 2019, he went to his grandfather's house armed with a knife and wearing a black hoodie to cover his school uniform.
He attacked his grandfather in front of the doorway.
Justice Coghlan said when neighbours heard cries for help they ran outside to find the boy "kneeling next to (your grandfather) with your right arm raised in the air, striking your grandfather in his upper body".
When his grandfather opened the door, the assault began with a punch to the face.
By the time the boy was done, there were 24 stab and force wounds to the chest, abdomen, neck and back.
Justice Coghlan said the stab wounds on the victim's back were in a "clustered or monotonous pattern, suggesting your grandfather was relatively immobile at the time he was stabbed".
When paramedics arrived, the man was pronounced dead.
By 9.22am, the boy was back at school, removing his black hoodie in the toilets before going to class.
CCTV footage helped identify the killer and he confessed in a police interview, saying the victim "wasn't exactly a nice man".
"He did some things that were very, shall I say, creepy, to my sister," he said.
"You don't mess with my sister, no way.
"I did what I had to do."
The boy revealed to police that when his sister was between seven and nine years old his grandfather would stand in front of her naked, and give her beer.
He had not seen his grandfather for eight years before he showed up on his front doorstep to kill him.
Justice Coghlan said a mental health expert reported the boy was motivated by "hatred and derision."
"He considers his grandfather and … people who sexually abuse children to be worthless," he said.
Mental health experts said the boy was also motivated by the extremely negative view he held of his mother and his mother's family, including his grandfather, Justice Coghlan said.
The court heard the boy showed evidence of "splitting" following his parents' divorce when he was younger. This is where is where a person assigns solely good characteristics to one person and solely bad characteristics to the other.
He could show emerging signs of borderline personality disorder due to his black-and-white thinking, experts said.
But Justice Coghlan said there was "not a direct nexus between mental health concerns and the offence".
He said the reason for the killing "cannot be regarded in any way as adequate".
He found the murder was "situational" and the main risk of the boy reoffending when he was released would be a similar episode to the killing.
He said it was a "brutal murder borne out of anger" but it was not premeditated.
"Unlike the predominant majority of young men who come before this court, you have no experience with the criminal justice system," he said.
He noted the murderer had the "unqualified" support of his father and sister.
Justice Coghlan said the prison sentence would have been significantly longer had the killer not pleaded guilty.
Originally published as Why teen stabbed his grandad to death