Investigators from Taskforce Wayward are appealing for witnesses after a teen was assaulted and robbed in Werribee on Monday.
Investigators have been told a 15-year-old boy was jogging around the grounds of a Greave Street primary school when he was approached by a group of 10 to 15 youths about 4.15pm.
Several members of the group assaulted the Werribee teen before fleeing with his mobile phone and shoes.
He was taken to hospital where he remains with serious but not life-threatening injuries.
Investigators believe a man and a woman, who were exercising in the area, may have witnessed the incident and are appealing for them to come forward.
The group were all perceived African in appearance and aged in their mid to late teens.
Anyone who witnessed the group, or with any information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au