Police are still investigating the incident, but believe it was a domestic situation that escalated into gunfire.
The victim, whose name has not been released, was transported to Intermountain Medical Center and was undergoing emergency surgery.
He later died of multiple gunshot wounds.
According to Sgt. Jon Arnold of the Sandy Police Department, the man found with the gun in his hand has been released without arrest after investigation and consultation with the Salt Lake District Attorney's office. A formal screening of the case will be conducted later this week.
Stay tuned to ABC 4 News and ABC4.com for more on this story.