Officer Doug Taylor says the football brawl leading to the expulsions of six high school students stemmed from an argument between two rival gangs.
Taylor testified Thursday at a preliminary hearing for four students charged as adults in the September brawl.
The expulsions brought Jesse Jackson to Decatur to protest on the boys' behalf. Under pressure from Jackson, their two-year expulsions were cut in half and the teens were allowed to enroll in alternative schools.
Jackson still wants to see the boys reinstated at their regular schools.