Waterloo Regional Police have issued a call for video footage from anyone who was at Victoria Park on Monday night.
Police say there were 18 calls for service at the park on the night of Victoria Day.
They are continuing to investigate a number of incidents that were reported at the park that night, including assaults, people with weapons, and fireworks being shot into crowds and at bylaw and police officers.
Video footage can be submitted to police by using the Waterloo Regional Police Service Evidence Submission Portal.
Police said that two officers were left with minor injuries as a result of being struck by fireworks at Victoria Park on Monday.
They said there were 500 people in attendance who were expecting to see fireworks that night, and it took several hours for them to disperse.
There were two men from Kitchener arrested on Monday night in regard to separate incidents, with one facing an assault charge while the other was charged in connection with fireworks being shot at crowds of people.