But while the Crown argued the incident was an aggravated robbery that went wrong, defence counsel for the boys said there was a lot more to it.
The court heard evidence that the older defendant suffered a severe head injury after being hit by a car six years ago which landed him with a reduced mental capacity, particularly in "complex" situations.
According to one witness, who was with the boys before the incident, it had been the 13-year-old's plan to commit an illegal act that day.
His lawyer David Niven said the original idea was to break into a nearby shoe shop.
The change of plan to hit the dairy came at the eleventh hour, Mr Niven said, and they would have had less than three minutes to plan the theft.
CCTV footage played numerous times for the jury showed the younger defendant standing in the doorway of the dairy while his friend was inside.
Mr Niven said by the time the scuffle between the knife-wielding teen and Mr Kumar began, his client had run off.
He told the jury the boy reacted like that because he had never planned for or expected violence.
The jury agreed.
Video from inside the shop shows Mr Kumar's wife Anita walking in with a phone to call police. The 14-year-old swipes it out of her hand and immediately draws a knife. He backs the dairy owner towards the till at knifepoint and, when the man attempts to force him back, slashes and stabs at him with the knife.
When Mrs Kumar returns, having raised the alarm at a neighbouring business, the pair can be seen scuffling near the doorway and the teen plunges the knife into her husband's neck.
Seconds later he runs off as the man collapses on the floor.
Name suppression continues until a hearing on July 29, two days before the 14-year-old is sentenced.
The 14-year-old is one of about 10 children. It is understood his mother gave birth to her youngest child weeks ago.
A source close to the family said the children had a tough upbringing and most had been in and out of Child Youth and Family care.
"They have been through absolute hell, and then this happens ? it sucks. [The 13-year-old] is actually a little sweetheart that, with the right support in place, could have grown into a strong and contributing member of society.
"I feel absolutely devastated knowing that this could have been prevented. It's just horrible."
Arun Kumar's son Shivneel, speaking outside court, said they were "extremely disappointed" with the jury's verdicts.
"The heart and soul of our family was taken away," he said.
The family had attended court in pursuit of justice, Shivneel said, but instead had repeatedly "re-lived the worst day of our lives".
"We endured countless reruns of my dad's last moments. We tolerated all this to obtain justice for my dad," he said.
But the stories of the defendant's dysfunctional upbringing and an explanation of self-defence by the older boy made the family feel as though they were the ones on trial.
"We listened to the stories of abuse and crime and how they believed it should exonerate the children," Shivneel said.
"We listened to the horrific details and excuses."
He had been at court every day with his distraught mother Anita, who clung to him as he addressed reporters.
They felt like the process had all been for nothing, he said.
"Few can ever understand what we went through and continue to go through in our daily lives."
Despite the outcome, Shivneel said he hoped lessons were learned.
"We are now living in a society where kids are on drugs, roaming the streets with weapons at the ready," he said.
"My dad's death should not be in vain."
