A 4-year-old boy accidentally shot his pregnant mother after finding a loaded handgun inside their suburban Seattle home, authorities said.

The woman, who is eight months pregnant, and her boyfriend were in bed watching TV on Saturday afternoon when the boy walked in, found the handgun and shot his mother in the face, said Sgt. Ryan Abbott, a spokesman for the King County Sheriff’s Office.

The weapon was placed between the bed mattress and the box spring, and the boy found it there, Abbott said. The mother was rushed to a hospital with life-threatening wounds, though she is now in stable condition.

Her boyfriend, who is also the boy’s father, is under investigation for not securing the gun, which he borrowed from a friend, and “putting somebody at risk,” Abbott said.

The accidental shooting happened just months after Washington state voters approved a controversial initiative that would, among other things, hold a person criminally liable if he or she fails to properly secure a gun that was then fired by someone who can’t legally use it, i.e., a child or a felon.

Initiative 1639, a sweeping gun control proposal that voters approved in November, would also raise the minimum age to buy a pistol or semiautomatic rifle to 21. It would impose more background checks and longer waiting periods for sales or delivery of semiautomatic rifles.

Gun rights advocates and several sheriff’s departments have strongly opposed the initiative, which immediately prompted lawsuits from the Second Amendment Foundation and the National Rifle Association. Several sheriff’s offices have announced that they will not enforce the initiative until legal challenges have been resolved.

“I am instructing my deputies not to enforce Initiative 1639 in Grant County while the constitutional validity remains in argument at the federal courts level,” Grant County Sheriff Tom Jones said in a statement Monday. “I swore an oath to defend our citizens and their constitutionally protected rights. I do not believe the popular vote overrules that.”

Parts of Initiative 1639, including the gun storage provisions, won’t be in effect until July — meaning it would not be a vehicle to criminally charge the boy’s father. Abbott said an investigation is ongoing, and the father, whom officials have not named, could face charges such as reckless endangerment.

Still, the shooting comes as Washington state officials and gun-control advocates have been pushing for laws on properly storing weapons at home. The Washington Post’s Christopher Ingraham has documented hundreds of cases in which children accidentally shot themselves or someone else in their household.

In King County, which covers the suburb where the family lives, council officials recently approved a law imposing fines of up to $1,000 for failing to safely store firearms. The cities of Seattle and Edmonds have passed similar ordinances.

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