Dau Akueng, 15, and a 12-year-old boy were fatally attacked while walking home from a local basketball match at Cobblebank in Melbourne's outer northwest on Saturday evening.
The alleged offenders remain on the run, with police describing the incident as having the "hallmarks of a youth gang crime".
Officers believe the attacks were targeted but will also probe if they were a case of mistaken identity.
"The children who were murdered were not gang members and it is not OK to remain silent," Detective Inspector Graham Banks told reporters on Sunday.
The 15-year-old's father, Elbino Akueng, visited the scene, demanding answers after his son's death.
"My son is just gone like this - he was a basketball player, not a criminal," he said.
Witness reports and CCTV vision showed the killings were committed by a group of face-masked males armed with machetes and long blades.
Two crime scenes were established, including one outside Jatinder Kaur's home on Marble Drive.
She told AAP her daughter first alerted her to the attack after seeing flashing lights out the window.
Ms Kaur said her children struggled to sleep due to the fear of what occurred.
"It's too scary for them," she said.
Another crime scene was established on Cobble St, near Christopher McFarlane's property.
He discovered one of the youths' bodies after hearing noises outside his home.
Mr McFarlane said he witnessed eight people, brandishing machetes, jump into a large car just before 8pm.
He now feels unsafe in his neighbourhood, adding that he usually walked his dog at that time.
"This is such a safe area, but now that's all gone," Mr McFarlane said.
"Everyone's just devastated and shocked. We've just got the machete bins in - they haven't done much good."
Victoria's machete ban came into effect on September 1, with the community urged to dispose of the weapons in specialised bins located at 45 police stations across the state.
The latest crime statistics showed crimes committed by children aged 10 to 17 jumped 17.9 per cent in the 12 months to the end of March.
It was the second successive quarter of record youth crime rates since data collection began in 1993.
Police are appealing for witnesses to come forward, including anyone with dashcam footage of the incidents.
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