Cyanide device explodes, killing family's dog. They can't believe who planted it behind their home.

Canyon Mansfield was on a walk Thursday with his dog Casey on a hill behind his family's Pocatello, Idaho, home  when he noticed a pipe-like object sticking out of the snow-covered ground.

“I go over and touch it," Mansfield, 14, told the East Idaho News. "Then it makes a pop sound, and it spews orange gas everywhere.”

The gas was cyanide, the paper said, and it hit Mansfield's left eye and clothing. So he washed out his eye with snow, the News said.

But then he noticed his dog was in trouble. Turns out the wind blew the cyanide right into Casey's face, the News reported.

“I look over and see him having a seizure,” the tearful teen told the paper. “I ran over, and he had these glassy eyes. He couldn’t see me, and he had this red stuff coming out of his mouth. So I was freaking out.”

Image source: YouTube screen cap

Mansfield sprinted down the hill and told his mother Theresa what had happened, the News reported, and the pair ran back up to attend to Casey — but their 3-year-old yellow Lab was dead.

The Mansfields' dog, Casey, died when the wind blew the cyanide into his face. (Image source: YouTube screen cap)

Theresa Mansfield called police and then her husband Mark, a medical doctor, the paper said.

“I hurried home, and the first thing I did was try to resuscitate the dog,” Mark Mansfield told the News. “Unfortunately, I exposed myself to cyanide and had no idea.”

Image source: YouTube screen cap

After hours of investigation, the paper said it was determined that their dog Casey was exposed to an M-44 — a spring-activated device that releases cyanide when it's pressed or pulled upward. The News added that the U.S. Department of Agriculture employs the M-44s for coyote control.

Image source: YouTube screen cap

The revelation was no relief to the Mansfields, whom the paper said had never seen such a device in their neighborhood during the 10 years they've lived there.

“We didn’t know anything about it. No neighborhood notifications, and our local authorities didn’t know anything about them,” Mark Mansfield told the News. “The sheriff deputies who went up there didn’t even know what a cyanide bomb was.”

The family told the paper the M-44 that killed their dog was planted on their property's border.

“We weren’t aware, and nobody told us,” Theresa Mansfield told the News. “There was nothing posted up on the hill saying to beware or be careful.”

Image source: YouTube screen cap

The Mansfields, along with responding deputies, had blood drawn to make sure they were in the clear after the cyanide exposure, the paper said.

The U.S. Department of Agriculture Wildlife Services told the News the incident was Idaho's first unintentional M-44 discharge since 2014.

“Wildlife Services understands the close bonds between people and their pets and sincerely regrets such losses,” R. Andre Bell, a spokesman for the USDA, told the paper in a statement. “Wildlife Services has removed M-44s in that immediate area … and is completing a thorough review of the circumstances of this incident … to determine whether improvements can be made to reduce the likelihood of similar occurrences happening in the future.”

But many unanswered questions remain.

For one, the clothes Canyon Mansfield was wearing at the time of the cyanide explosion are in a sealed plastic bag, the News said — his family isn't sure what to do with them.

Image source: YouTube screen cap

“We couldn’t even have a proper burial for Casey because we didn’t know how to deal with cyanide,” Theresa Mansfield told the paper. “No one knows how to deal with cyanide.”

Image source: YouTube screen cap

And while another M-44 was found about 50 yards from the first device, the Mansfields told the News they're not sure if there are others.

“Three hundred yards from this swing set next to my house, there were two cyanide bombs," Mark Mansfield told the News. "It kills anything. It almost killed my child, and it did kill my dog. I don’t want it to kill my neighbors.”

Also, the Mansfields told the paper that as of Friday no one from the USDA apologized to them for the incident.

“If you plant bombs by our house, just tell us,” Canyon Mansfield told the News. “By the grace of God, I’m still alive.”