Story highlights The boy's father calls for gun safety

Three other children are in the house

"You have got to be more diligent," police chief says

A 3-year-old boy in a small Michigan town was killed over the weekend when he accidentally shot himself in the head with a gun he found on the closet floor of his home.

The shooting death will undoubtedly renew the debate about gun safety, particularly after the boy's father took to Facebook calling for it.

The incident took place Sunday at a home in Dundee, near the Ohio border.

Police said Damon Holbrook discovered the gun, which belonged to a family friend who was living in the house.

Authorities told CNN affiliate WXYZ that the family friend, Joshua Greenhill, had a concealed pistol license and he put the .40 caliber handgun in the closet. It was loaded, with a bullet in the chamber -- but was not locked.

Three other children were in the house at the time.

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Greenhill, was charged with careless discharge of a firearm -- a misdemeanor which carries a sentence of up to 2 years in prison or a fine of $2,000. He didn't speak to reporters after his court appearance Monday.

"We are working on a more serious charge at this time. We have not completed our investigation," Dundee police Chief David Uhl told reporters. "You have got to get more diligent with the guns. Be a lot safer with them."

'My boy would still be here'

After the shooting, Damon's father, Brian Holbrook, posted this message on Facebook: "I have nothing wrong with guns it's with this country was built on. I will still support the Second Amendment.

"All I ask is that everyone please, please safety first lock it up and put it out of reach of anyone that has no business being around a gun especially kids.

"Gun safety people! My boy would still be here if it was put away like it should have been."

In May, a southern Kentucky mother stepped outside her home just for a few minutes, but it was long enough for her 5-year-old son to accidentally shoot and kill his 2-year-old sister with the .22-caliber rifle he got for his birthday.

Firearm deaths of kids rare

But despite the recent incidents, accidental firearms deaths are rare among children.

According to the CDC's National Center for Injury Prevention and Control, 703 children under the age of 15 died in accidental firearms deaths between 2001 and 2010, the latest year for which the agency's statistics on fatalities are available.

During the same period, 7,766 children under the age of 14 suffered accidental firearms injuries -- about one injury for every million children.

But statistics don't matter much if it's your child that's shot, said Missy Carson Smith, founder of Gun Safe Mom, a campaign to make the gun question as common as asking about food allergies, swimming pools and video game limits.

"It just shreds your family," said Smith, whose own teenage brother died in a shooting. She started the campaign in 2009, after learning during a carpool trip that unsecured guns were in the home of a family where her daughter had played.

"The kids knew where they were, they could get to it," she said. "That's when my heart just dropped in my stomach."