The WA Supreme Court has heard a teenager used a filleting knife to "intentionally and deliberately" stab a Perth man to death when he tried to retrieve a stolen bicycle.
The 15-year-old, who cannot be identified, is alleged to have murdered 42-year-old Petr Levkovskiy on a Sunday morning in May last year, in the southern suburb of Bull Creek.
On the first day of the trial, which is listed for 10 days, prosecutors told the court Mr Levkovskiy and his wife had been trying to help a 10-year-old boy retrieve his mountain bike, which had been stolen earlier by the teenager.
The stabbing happened around 10:30am after the father of two told the teenager "let's talk" and put his arms around him, before the teen grabbed a filleting knife and "plunged" it into the 42-year-old's abdomen.
Mr Levkovskiy immediately collapsed and died later in hospital from his injuries.
Teen admitted to stabbing in video recording
Prosecutor Paul Usher told the court that two hours later, a friend recorded the teenager demonstrating how he stabbed Mr Levkovskiy, before putting up his two middle fingers to the camera.
In the video, the friend could be heard asking the accused to "tell us who you killed today", to which he responded: "I just stabbed."
He is also alleged to have said he did not feel bad about what had happened.
The jury was told that after the stabbing, the teenager fled the scene and discarded the knife and some items of clothing, which he attempted to retrieve but they had been discovered by police.
It is also alleged that as the 10-year-old and his three friends chased the teenager after he had stolen the bike, he was heard to say "come here and I will shank you".
Mr Usher said after finding out Mr Levkovskiy had died, the accused later told his mother he had stabbed him and that "a group of boys had provoked him so he stole one of their bikes".
Accused allegedly tried to flee to Japan
The jury heard he later asked his father for his passport so he could go to Japan and also said he had "done something serious," but his father refused.
The teenager was arrested by homicide squad officers the next afternoon.
The state prosecutor said the boy had come into possession of the knife months earlier and it was alleged he had armed himself with it "with no intention but to use it on another person when the time arises".
Mr Usher described the stabbing as very "precise", "deep", "deliberate" and "intentional".
He said the teenager "exhibited limited surprise" when he found out about Mr Levkovskiy's death and that his actions were "inconsistent with someone who intended a lesser harm".
The teenager has pleaded not guilty to the murder charge.
Jury urged to consider manslaughter conviction
The teenager's defence lawyer did not dispute that the accused was guilty of an offence, but urged the jury to consider a conviction of manslaughter instead of murder.
Simon Freitag SC claimed the teenager had already ditched the stolen bike by the time Mr Levkovskiy caught up to him and that it was during a brief struggle between the pair that he was stabbed.
He said while the teenager had made some poor choices, it did not make him a murderer and that he intended to stab Mr Levkovskiy on his leg, rather than his abdomen.
"The state says it was a precise stab [but] nothing could be further from the truth," Mr Freitag said.
"This is not where you would stab someone if you were intending to endanger life."
He told the jury the accused was a "15-year-old kid [who] did not have a mature view of the world."
