Police say it appears to be an accidental shooting.

In what investigators are calling a bizarre case, the gun belongs to a 16-year-old girl. She kept the loaded gun under her mattress for protection, and investigators tell KOMO 4 News her father gave it to her to have, just in case.

Now, you might think it's illegal for a 16-year-old to possess a gun, but in this case you would be wrong.

"It's normally illegal for a 16 year old to possess a loaded firearm," said Thurston County Sheriff's Chief Criminal Deputy Dan Kimball. "Except in the case of an exception like hunting or the other exception would be in your own home under parent approval. There's no criminal act here on parent or on the 16-year-old who possessed it."

Chief Kimball says that on Monday night, the girl reached for that gun -- not to protect herself, but to show it to friends. Investigators say while the girls parents slept, she passed around her gun. 18-year-old Daniel Coots of Olympia, who police say had been drinking, was holding the gun when it went off. A 19-year-old man was shot in the head.

"It struck the 19-year-old, who was across the table from it and it hit him in the head just below the eye," Kimball said.

Ironically, a new Harborview and UW study shows that having a gun locked was associated with a 73 percent reduction in risk injury. But researcher Dr. Doug Grossman says safety doesn't stop with locking guns.

"Locking your gun, unloading your gun, keeping your ammunition locked and keeping that ammunition stored separately from the gun," says Dr. Grossman.

Kimball agrees.

"We would not recommend minors having firearms at any time outside the immediate supervision of a responsible adult. Not only can kids make poor choices their friends can make poor choices." He added that a poor choice critically injured an Olympia teen.

The Sheriff's Office says it's an accidental shooting, but Coots could faces possible reckless endangerment, drug and alcohol-related charges.

Investigators also found marijuana in the 16-year-old's room.