Four-year-old boys in different states were involved in two separate shooting incidents in the last four days, with tragic results.

On Saturday, a Tennessee boy discharged a pistol at a sheriff's deputy's wife, killing her instantly. On Monday, a New Jersey toddler killed a 6-year-old neighbor after a rifle was fired at his head.

The Tennessee incident occurred during a family cookout at the home of Josephine and Daniel Fanning. He's a sheriff's deputy in Wilson County.

Deputy Fanning, 51, was in his bedroom showing his collection of weapons to a relative around 7:00 p.m. Saturday, when Josephine, 48, and the 4-year-old came into the room. The young boy grabbed a loaded handgun sitting on the bed and fired it once, striking and killing the deputy’s wife, according to Tennessee Bureau of Investigations spokeswoman Kristin Helm. She was pronounced dead at the scene.

The incident appears to be an accident and no one has been charged, but the investigation is still open, according to Helm.

“It’s a sad, sad set of circumstances,” Sheriff Robert Bryan told NBC affiliate WSMV in Nashville. "Nobody is immune to this. Nobody. It doesn't matter if you are a law enforcement officer. These things can happen in second."

The 4-year-old is a relative of the deputy and his late wife, WSMV reported. The weapon used by the 4-year-old boy was not Deputy Fanning’s service weapon.

Another tragic incident took place in New Jersey on Monday evening, when a 4-year-old boy accidentally shot a 6-year-old neighbor with a rifle he found in his parents’ home.

Police said the two boys were playing with a .22-caliber rifle outside the 4-year-old’s home in Toms River, N.J., when around 7:00 p.m. the gun discharged and struck the 6-year-old in the head, NBCNewYork.com reported.

The 4-year-old's parents reportedly heard the shot and called 911.

According to NBCNewYork.com, the 6-year-old was taken to Jersey Shore Medical Center, where he later died. An investigation is ongoing.

Shawn Moore / AP

This undated photo provided by Shawn Moore shows his son Josh, 10, holding a rifle his father gave him for his 11th birthday, at their home in Carneys Point, N.J.

The ruddy-cheeked, camouflage-clad boy in the photo smiles out from behind a pair of glasses, proudly holding a gun his father gave him as a present for his upcoming 11th birthday.

The weapon in the photo, posted by his dad on Facebook, resembles a military-style assault rifle but, his father says, is actually just a .22-caliber copy. And that, the family believes, is why child welfare case workers and police officers visited the home in Carneys Point last Friday and asked to see his guns.

New Jersey's Department of Children and Families declined to comment specifically on the case but says it often follows up on tips. The family and an attorney say father Shawn Moore's Second Amendment rights to bear arms were threatened in a state that already has some of the nation's strictest gun laws and is considering strengthening them after December's schoolhouse massacre in Connecticut.

In this case, the family believes someone called New Jersey's anonymous child abuse hotline.

Shawn Moore said he gave his son Josh the gun as a present to use on hunting trips. The elder Moore was at a friend's house when his wife called, saying state child welfare investigators, along with four local police officers, were at the house, asking to inspect the family's guns.

Moore said he called his lawyer Evan Nappen, who specializes in Second Amendment cases, and had him on speakerphone as he arrived at his house in Carneys Point, just across the Delaware River from Wilmington, Del.

"They said they wanted to see into my safe and see if my guns were registered," Moore said. "I said no; in New Jersey, your guns don't have to be registered with the state; it's voluntary. I knew once I opened that safe, there was no going back."

With the lawyer listening in on the phone, Moore said he asked the investigators and police officers whether they had a warrant to search his home. When they said no, he asked them to leave. One of the child welfare officials would not identify herself when Moore asked for her name, he said.

The agents and the police officers left, and nothing has happened since, he said.

"I don't like what happened," he said. "You're not even safe in your own house. If they can just show up at any time and make you open safes and go through your house, that's not freedom; it's like tyranny."

State child welfare spokeswoman Kristine Brown said that when it receives a report of suspected abuse or neglect, it assigns a caseworker to follow up. She said law enforcement officers are asked to accompany caseworkers only if the caseworkers feel their safety could be compromised.

"It's the caseworker's call," she said. "It is important to note the way an investigation begins is through the child abuse hotline. Someone has to call to let us know there is a concern."

Carneys Point Police Chief Robert DiGregorio did not answer a call late Tuesday to his office.