A 17-year-old has been jailed for life for murdering his stepmother after he became "obsessed" with watching extreme violence online.
Rueben Brathwaite used an axe and a samurai sword to kill dog rescuer Fiona Scourfield, 54, at their countryside farm before trying to upload pictures of her body to the internet.
Swansea Crown Court heard on Friday how the teenager developed an interest in videos of beheading, suicide, and mass murder on "imageboard" website 4chan in the run up to the "horrific" murder.
A court heard Brathwaite immediately made a 999 call to confess to the killing, telling an operator he had become "fed up" with his life.
Prosecutor Paul Hipkin said the teen had lived with his landscape gardener father, Charles Brathwaite, and his stepmother at their log cabin on Broodmoor Farm in St Clears, Carmarthenshire, West Wales, where he began accessing images and videos of "brutal" violence online.
Mr Hipkin said: "In the lead up he accessed images of killings of some brutality on the internet via a website in the USA.
"The images demonstrated murder, death and mutilation."
Brathwaite decided to carry out the attack after returning home from school on March 6 this year, after first considering killing her the night before.
He collected an axe while tending to his family's livestock and a samurai sword which was kept under his father's bed.
He said he called to his stepmother to come outside to check on their cat, and when she did he struck her to the skull with the blunt side of the axe, before repeatedly striking her head as she lay on the floor.
He then used the samurai sword to repeatedly slice and stab at her neck.
In the 999 call made to police he said: "I've just killed someone.
"The person is Fiona Scourfield.
"I know she's dead. Her pulse has stopped. There's no signs of life.
"I hit her so many times in the head, about eight to nine times with the axe."
Asked why he had killed her, Brathwaite told the operator: "I'm just fed up with my life.
"I wanted to commit suicide but I couldn't.
"So I thought if I killed someone else it would get me out."
He later told police: "She takes good care of me. I'm sure she loves me and my father.
"I just wanted her dead so I could have a life."
He said he chose to try and knock his stepmother out before slicing her throat because he wanted to "kill her without distress, really".
Brathwaite admitted trying to then upload photos of Mrs Scourfield's body to the American website 4chan, where anonymous users share content, but was unsuccessful.
He was arrested by Dyfed-Powys Police walking near the farm and later pleaded guilty to murder at a hearing at Swansea Crown Court.
Paul Hobson, defending, said Brathwaite had watched violent content regularly in the months leading to the killing.
Mr Hobson said: "He realises what his approach to viewing that material must have had on his thinking.
"After time a natural revulsion to pain and crime became deadened to him."
Judge Mr Justice Simon Picken said Brathwaite had complained of loneliness, unhappiness and depression leading up to the attack, but had not been suffering from any mental health condition.
The judge said: "The savagery of the attack on this defenceless woman makes this case all the worse.
"No doubt inspired by the graphic images seen on the internet in the months before the attack, you attempted to upload images of the attack to the internet.
"Your obsession went to watching material including mass murders and massacres."
Brathwaite was jailed for life with a minimum term of 15 years.