The stabbing murder of a young father has been "a death sentence for his family", his sister has told a court.
The "utterly devastating effect" of the murder on Jordan Powell's loved ones was laid bare in the ACT Supreme Court on Tuesday, when the 29-year-old's killer faced a sentence hearing.
Counsel for the killer, Kenan Dowden-Carlisle, also informed the court of the offender's remorse, reading a letter in which he apologised to the victim's family for his "horrible" actions.
Dowden-Carlisle, 20, pleaded guilty in February over the murder of Mr Powell, which occurred in a laneway beside a Civic pub in December 2021.
Prosecutor Anthony Williamson SC revealed the details of the crime for the first time on Tuesday, telling the court Dowden-Carlisle had mistakenly suspected Mr Powell of stealing a satchel that contained his drugs.
An agreed statement of facts shows the heavily intoxicated killer had in fact left the bag in a Queanbeyan motel room.
Unaware of this at the time, he and Mr Powell "shaped up" to each other in Petrie Plaza about 8.30am on the day in question, then agreed to fight in Bible Lane an hour or so later.
Mr Williamson said Dowden-Carlisle was "set upon retrieving" the bag and was motivated, at least in part, by a desire to exact revenge on Mr Powell when they met in the alleyway.
The acting ACT Director of Public Prosecutions said while Mr Powell had reason to anticipate a fist fight, there had been nothing to alert the victim to the possibility he would be stabbed.
That is what happened when Dowden-Carlisle pulled out a tactical knife and used it instantly, puncturing Mr Powell's heart with a single strike.
Police quickly tracked down Dowden-Carlisle, a Queanbeyan resident, and arrested him in Ainslie Place after a short foot pursuit.
The killer has been behind bars on remand since the murder, which has left Mr Powell's four children and wider family struggling to comprehend his sudden death.
Some members of the family detailed their struggles in victim impact statements read on their behalf by Mr Williamson.
Mr Powell's elder sister, Amanda Coe, described herself as being more like a mother to the victim, who had been "the kindest, humblest, cheeky kid going".
Ms Coe wrote that she was still in denial, 18 months after the death of the young father nicknamed "Ducky".
His death had caused her to withdraw from her family, she said, telling the court she found it too hard to see the pain on their faces.
"It's a death sentence for his family," Ms Coe said of Mr Powell's killing.
Stephanie Clarke, the mother of Mr Powell's eldest child, described the difficulty their 11-year-old son had comprehending his father's death.
She addressed Dowden-Carlisle directly, telling him she hoped he would never have to bear the loss of a parent or watch his own children deal with that sort of grief.
"You, Kenan, are a threat to society," Ms Clarke wrote in her victim impact statement.
Mr Williamson told the court the statements made it clear the impact of Mr Powell's death on his relatives had been "utterly devastating".
The prosecutor described the murder as "cowardly", noting Mr Powell had been an unarmed and unsuspecting victim.
He also said Dowden-Carlisle had been under the influence of Xanax and alcohol at the time of the killing.
The murderer's own comments to a pre-sentence report author reflected his knowledge of the fact a combination of these substances tended to make him angry, the prosecutor added, telling the court this was "a matter of serious aggravation".
Mr Williamson went on to describe Dowden-Carlisle's prospects for rehabilitation as guarded, highlighting the fact he had been "a poorly behaved prisoner" while remanded in custody.
Dowden-Carlisle wrote a letter of apology to Mr Powell's family, telling them he was "deeply sorry" for their loss and saying he knew he deserved any consequences that came his way.
But Mr Williamson questioned the sincerity of those words, noting the killer had been caught twice, as recently as March this year, with improvised blades in his Canberra prison cell.
Dowden-Carlisle's barrister, Kylie Weston-Scheuber, described the murder as the result of "a moment's stupidity, in the midst of being affected by alcohol and drug use".
She stressed that the killing had not been premeditated, telling the court Dowden-Carlisle's friend had suggested a fight with Mr Powell and the victim had accepted the invitation.
Dr Weston-Scheuber told the court Mr Powell had thrown the first punch, striking Dowden-Carlisle in the head, before the killer stabbed him with a knife he had obtained hours earlier.
She described the killer's conduct as "an escalation of risk-taking behaviour", rejecting Mr Williamson's claims of "underworld enforcement" or some sort of vigilantism.
Acting Justice Stephen Norrish indicated he would hand down a sentence on July 7.
