MANKATO (AP) - Authorities have released the three people who were arrested after a fatal shooting at a Mankato nightclub over the weekend.

Blue Earth County's chief prosecutor said Monday that he's not sure when his office will file charges in the case. Authorities have 48 hours in which to file charges following an arrest.

Four people were shot, one fatally, outside the Kato Ballroom early Sunday following an event for a Sudanese student group from Minnesota State University.

Investigators are still trying to determine what transpired.

Police arrested one person for allegedly carrying a gun without a permit and two others for suspicion of obstruction of the legal process. County jail staff confirmed that all three have been released.