The fatal shooting took place in rural Kansas along a road in Sumner County, about 45 miles south of Wichita, Wellington Fire and EMS Chief Tim Hay told USA TODAY on Wednesday.

The Sumner County Sheriff’s Office identified the victim as Joseph Austin Smith of Wichita.

According to the sheriff's office, deputies were dispatched to the scene Saturday morning for a male who had been shot in the back. 

At the scene, EMS personnel administered CPR before the victim was pronounced dead, Hay said.

The driver of the truck, who was sitting next to Smith when the gun fired, was not hurt, Hay said.

Hunting gear, a dog and a rifle in the back seat

Sheriff's office Deputy Jordan Douglas said a preliminary investigation found Smith was sitting in the front passenger seat of a pickup that contained hunting gear and a rifle in the back seat.

A dog who deputies said belonged to the owner of the pickup, was also in the backseat and stepped on the rifle, causing it to fire.

"The fired round struck the passenger who died of his injuries on scene," sheriff's officials wrote in a press release.

The case remained under investigation on Wednesday, Douglas said.

On Wednesday, Hay reminded gun owners to store firearms properly when in vehicles.

"Keep the safety on, unload your guns completely when it's in a vehicle and put it away, in the trunk," he said.