A fistfight between members of two "motorcycle clubs" at the National Western Stock Show in Denver escalated into an incident that left four people shot -- one fatally -- another stabbed and three others injured, police said.
The incident occurred at the first day of the Colorado Motorcycle Expo. The second day of the show, which was supposed to continue tomorrow, was cancelled.
Denver Police Chief Robert White said no one has been arrested, but police were speaking to a "person of interest."
"We are interviewing several witnesses and we do have one person of interest who we will be interviewing also," he said.
There appears to have been more than one shooter involved and there was "an exchange of gunfire," White said.
More than 10,000 people attended the event, and they were not required to pass through metal detectors to get in, the police chief said.
"We will have to assess whether this event will be held again if at all in this city," Denver Director of Safety Stephanie O'Malley said.
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.
The Associated Press contributed to this report.