Three-year-old kills baby sister with ‘unsecured handgun’ left in California home

san diego toddler shooting
The San Diego County Sheriff's Department arrived at the scene at 7:30am on Monday - NBC San Diego

A toddler has killed their one-year-old sister with an “unsecured handgun” left in a California home, authorities said.

The San Diego County Sheriff’s Department arrived at the scene after receiving a call about a shooting in Fallbrook, about 55 miles north of San Diego, at 7:30am on Monday.

The department said officers found the toddler had managed to get hold of the weapon and the one-year-old had sustained a head injury.

“Fire department personnel arrived on the scene and transported her to Palomar Hospital. Despite lifesaving efforts, she was pronounced deceased at about 8.30am,” it added.

Neither of the children have been named.

Neighbour Rick Stephens told NBC San Diego that he was shocked by the incident.

“I have grandkids,” he said. “I told my kids: hide everything. If you have guns you put them in a safe and hide them with ammo. Kids will find anything, believe me. They look around and they find stuff that you never think they would find.”

‘No threat to the community’

Investigators were working to gather more information to determine the circumstances of the death.

“There are no outstanding suspects and there is no threat to the community. The investigation is ongoing,” the San Diego County Sheriff’s Department said.

It added that the San Diego County District Attorney’s Office had been notified of the incident and an autopsy will be conducted to determine the cause and manner of death.

According to the Gun Violence Archive, there have been 155 documented fatal shootings across the United States to date this year in which the victims were under the age of 11.

In California, there has reportedly only been one other fatal shooting this year involving a victim under the age of 11.