© Michael Milnes/News LimitedPolice investigators at the house in which Pirjo Kemppainen was murdered, on the day after the attack.
He was being cross-examined on Friday at the South Australian Supreme Court trial of his friend, who has denied murdering 63-year-old Pirjo Kemppainen.
The witness is serving a non-parole period of 15 years after previously pleading guilty to the murder, which occurred when both boys were aged 14.
The crown has alleged that despite the accused youth being across the road when his friend murdered Ms Kemppainen, he too was guilty as he was a part of their joint plan to kill her.
Ms Kemppainen was murdered at her Callington home in the Adelaide Hills in the early hours of September 11, 2010.
She suffered more than 120 injuries, including 39 stab wounds and 69 blows.
Under cross examination from defence lawyer Frances Nelson QC, the witness was referred to his arrest on September 14, 2010 and his comments to police.
He agreed he said: "There goes my acting career, I will probably get 10 years do you think."
When the officer said he could not talk to the boy, he continued: "My friends are probably right, maybe I am a psychopath."
The teenager also said: "I try not to let it get to me, people have done worse things in the world." The trial is continuing.
Or at least self-awareness of what he is, or could be, as perhaps he is too young to have come across that defined designation yet. He seems to be waking up to his role and accepting it, without any emotional qualms, without any concern for the police hearing his inner monologue as it turns out. This seems to be an interesting phase of 'awakening' for this young psychopath as the program turns on and autopilot is willingly accepted or embraced? Or does it matter? In a time of global acceptance of 'them', he seems to see the world like a predator drone developing self-awareness. Interesting, and so little concern over the loss of his 'acting career', is that because being aware of what he is means no longer needing to 'act'? Was he doing much of that before?