Two teenagers accused of murder were not "scared little boys" but were instead armed robbers who targeted the friend of a small-time drug dealer, a court has been told.
The teenagers pleaded not guilty on Monday in Brisbane Supreme Court over the stabbing death of 15-year-old Angus Beaumont on March 13, 2020 at Redcliffe.
Angus was stabbed after he and a 16-year-old companion were involved in a confrontation with the two accused, then both aged 14, on a footpath just after 8pm.
The charges are being retried before a judge alone after the two teenagers successfully appealed their previous convictions in July.
Crown prosecutor Chris Cook told the court on Monday that Angus had left home soon after finishing school and within four-and-a-half hours he was lying dead beside a major road in Redcliffe.
The court was played police audio in which one of the accused teens claimed the pair acted in "self defence".
"(Angus) had a big f***ing knife, my mate defended me," the teen said.
He told police they had bought cannabis from Angus's companion but were given less than they paid for.
"We chased him, we didn't want to hurt him, we just wanted our stuff back," the teen said.
Mr Cook said the audio also revealed the two teens needed drugs and knew Angus's companion had a larger supply in his bag.
"They were not scared little boys. They were hanging around the skate park with knives looking for drugs. They were prepared to use them," Mr Cook said.
He described Angus's companion as a "wannabe drug dealer" who carried knives and a knuckle duster, and who had walked to a skate park with Angus, another teenage boy and girl.
The 16-year-old had sold the two accused teens a "stick" of cannabis weighing 1.5 grams for about $25.
"He was not a good drug dealer ... he ended up showing (the accused teens) his drug stash. This was a fatal mistake," Mr Cook said.
The 16-year-old was chased through the park by the two accused teens before reaching the road where he was reunited with Angus.
The court was shown CCTV footage of Angus being hit and collapsing soon after.
Mr Cook said an autopsy showed Angus died from a 137 millimetre wound that punctured his chest wall and heart.
"(Angus) was a larger size but they were not deterred. He was attacked two-on-one and while he was distracted he was stabbed in the heart," Mr Cook said.
He said the teens should be both be convicted of murder, one for attacking Angus with at least the intent to cause grievous bodily harm and the other for having aided and encouraged the stabbing.
The barristers for the two accused teens, Patrick McCafferty KC and Jacob Robson, provided their opening statements to the court in writing.
The trial is due to run for another nine days before Justice Sean Cooper.
