The 16-year-old boy died in hospital after he was assaulted in a Balga park on December 22.
Four teenagers were charged with grievous bodily harm over the incident, but the charge was later upgraded to murder.
Police this month released images of three males they believe can assist with investigations.
One of them was described as 18-to-25-years-old, with fair skin, average height, slim build and short light hair.
He was wearing black shorts, glasses and a white T-shirt with blue pattern.
Another was about 22-to-28-years-old, of short stature and average build.
He was wearing blue pants, a light grey jumper with dark grey sleeves, yellow shoes and glasses.
The third man was about 18-to-22-years-old, of average build and height and had olive skin.
He was wearing dark shorts and a white T-shirt with ‘Nautica’ branding on the front.