TREMONTON, Utah -

A 14-year-old Tremonton boy was killed while playing with a toy 1800s era replica cannon.

At about 7:30 a.m. Monday, police say the cannon fired some sort of projectile into the Robbie Ostberg's face, killing him.

The incident was being investigated as an accident, although police weren't sure what kind of propellant was used in the six inch-long replica that was meant for display only. A relative of the victim says the mini-cannon was sitting on the shelf in the home.

?He was playing with it,? says Shauna Spencer. ?He was looking at it. He's 14 years old. It went off, it just went off.?

Police say his older brother and father were in the home at the time. But Spencer says no one saw it go off.

?His brother may have been in there and witnessed it,? says Spencer. ?But he does not know how it actually happened."

Police say the toy cannon is considered a weapon. Most load it with gun powder. But in this instance police say it was a show piece not a weapon.

?It's not intended to be used to fire anything,? says Dave Nance, Tremonton police chief. ?It's about six inches long or so. It's just intended to be looked at.

Ostberg's neighbor is familiar with the toy cannons. He's seen them before.

"Depending on how much gun powder you put in it, it will go through a wall, kill a rabbit or small game," says Trevor Steinlicht.

The boy's father is an army veteran. And Spencer says he locks his guns.

But Steinlicht says the toy cannons are known to go off accidently.

"All it takes is for something to slip and the hammer to drop on it and it will go boom," says Steinlicht.

For now, a family is grieving with so many questions unanswered.

?It was a tragedy that shouldn't have happened,? says Spencer.

Nance said the boy was declared dead at the scene.