Officials said that two or three shooters opened fire at around 10pm in and around a vehicle at the Mississippi State Fairgrounds in Jackson.
Five people were shot and wounded in the attack including one police officer and four innocent bystanders.
Officers from multiple law enforcement agencies who were working the event responded to the scene and an unidentified man was shot and killed.
Hinds County Sheriff Tyree Jones said at a press conference late Saturday that the deceased man is believed to be one of the shooters and was likely killed by officer fire.
“We believe one of the law enforcement personnel discharged his weapon, and we believe at this particular time that the victim that is deceased is possibly due to the officer-involved shooting,” he said.
“We believe that individual that is deceased was actively involved in the incident that was reported regarding the gunfire and regarding the several shots that were fired.”
Two unnamed juveniles were taken into custody and a vehicle, two rifles and at least one pistol believed to be related to the shooting were recovered from the scene.
The five people who suffered gunshot wounds are in a stable condition in hospital and are not thought to have been involved in the initial shooting or the events leading up to it, said Sheriff Jones.
It is not clear what led to the initial exchange of gunfire but the sheriff vowed to get to the bottom of what happened.
“At this time, we do not know what the motive is or exactly what happened,” he said.
“We will find out exactly what happened. We will find out who’s all involved, and they should be held accountable and responsible for this very reckless incident.”
The sheriff would not reveal the identity of the officer or which law enforcement agency that they are affiliated with, saying it “will come out at a later date”.
The investigation into the shooting is still ongoing with the Mississippi Bureau of Investigation drafted in to assist.
The Mudbug Festival, which was billed as a family event with crawfish boil and eating contests, live performers and carnival rides, will remain closed on Sunday.
The annual event, which was held for the first time last year, started on Wednesday and was due to end on Sunday night with singer Bobby Rush closing as the headline act.