Between 5am and 6am, the victim, a 13-year-old male, was allegedly assaulted by several juveniles believed to be known to him at a reserve on Coolamon Boulevard.
It is further alleged a knife was produced, threats were made and property was stolen from the victim.
The victim received minor injuries and later attended St John of God Midland Public Hospital for medical treatment.
Police became aware of vision of the incident circulating online and commenced inquiries.
The investigation remains ongoing and detectives have identified a number of persons of interest.
Police understand the incident has caused considerable concern within the community and ask members of the public to remain calm and allow detectives to conduct their investigation.
Members of the community are strongly urged not to take matters into their own hands, threaten retaliation or publish the names, photographs or personal information of people believed to be involved.
Anyone with information, mobile phone vision or other material that may assist the investigation is urged to contact Crime Stoppers at www.crimestopperswa.com.au or call 1800 333 000.
Reports made to Crime Stoppers can be made anonymously.
