A 3-year-old boy shot and killed himself after he found a gun in his parents’ bedroom nightstand, a Florida county sheriff said Thursday.

Dispatchers received a call on Wednesday evening from a 16-year-old girl who said her 3-year-old brother had shot himself and wasn’t breathing, Volusia County Sheriff Mike Chitwood said in a news conference Thursday. 

Deputies responded to the home in DeLand, Florida, to find the boy had fatally shot himself, Chitwood said. The child’s parents had left their teenage daughter home watching her brothers, 7- and 3-year-old boys, while the parents went to the grocery store.

The 3-year-old went into his parents’ bedroom and removed a 9mm handgun from the nightstand drawer and shot himself, the sheriff said. Chitwood noted the trigger for the handgun needs just 4.6 pounds of pressure to pull the trigger.

“Not much,” he said.

The childrens’ father is a Florida state corrections officer who told investigators he normally kept his guns in a safe, but that they electronic lock had stopped working, Chitwood said. A second gun in the house was placed on top of a refrigerator in the kitchen.

Chitwood said his office was investigating the circumstances around the case and would refer its finding to the State Attorney’s office.

“I cannot imagine there’s anything in the law books that can punish that family more than what happened last night,” Chitwood said.

According to data analyzed by the advocacy group Everytown for Gun Safety, there have been at least 20 unintentional shootings by children in the U.S. so far this year, resulting in 9 deaths and 12 injuries. Last year, there were at least 324 unintentional shootings by children nationwide, resulting in 145 deaths and 189 injuries, the group said.

It was rare to see a child as young as 3 shoot themselves, Chitwood said, and the incident sends parents a chilling message. 

“To all parents that own guns: If you have little ones, even teenagers, you got to lock them up, you have to lock them up because you just don’t know,” he said.

The state Department of Children and Families responded to the scene and is continuing to dedicate resources and supervision to the family. The first responders involved will also be receiving services in light of the trauma of the incident, the sheriff’s office said.