DENVER (AP) —Denver’s police chief says one person was fatally shot and seven others were wounded when a fight broke out a motorcycle expo on Saturday.

Police Chief Robert White tells reporters that it was unclear what prompted the incident at the National Western Complex, where the Colorado Motorcycle Expo was being held this weekend. He says other events associated with the expo have been canceled.

White says investigators believe there was an exchange of gunfire. In addition to the person who was shot and killed, three others were shot. White says another person was stabbed and three others suffered injuries from a fistfight.

Police were keeping a heavy presence at the hospital where the injured people were being treated to prevent the incident from spreading from the expo.

Police are interviewing a person of interest, and White says investigators believe there was more than one shooter.