Members of the public who witnessed the attack or who have information that may assist police are asked to visit the Whakatāne Police Station and speak with an officer.
Police are also reminding the public to report disorder when it happens, but Mackinnon advises caution before bystanders intervene.
“Some of these individuals may be carrying weapons, so I urge the public to be careful before they intervene,” he said.
“Even filming from a safe distance can be helpful to police during the investigation.”