PETERBOROUGH, Ont. -- Police say a brawl involving up to 30 people in a Peterborough, Ont., park is now being investigated as a "hate-bias" incident.

Investigators say 20 to 30 youths were involved in a fight between two groups on the night of Aug. 11 in Del Crary Park.

Police spokeswoman Lauren Gilchrist says no charges have been laid and investigators say there is no evidence to indicate that the altercation was racially motivated.

But police said Tuesday that while the altercation was taking place a bystander yelled a "racial and derogatory slur," resulting in the incident being classified as a hate-bias incident.

Investigators define a hate-bias incident as an expression of bias, prejudice and bigotry directed against a stigmatized or marginalized group.

Gilchrist says the investigation is ongoing.