9-year old Oklahoma boy gets gun out of safe and unintentionally shoots 3-year old brother

A 9-year old boy was at home in Afton, Oklahoma, when he accessed the key to his family's gun safe.  He went into the safe and pulled out a gun, when he then unintentionally discharged.  The round hit his 3-year old brother in the leg.

Their mother was home at the time. 

The wound is not fatal.

From an article:

According to Ottawa County Sheriff's Detective Derek Derwin on June 6 at approximately 11:30 a.m the Baptist Integris Emergency Room received a 3 year old boy, with a gunshot wound to the leg.  Derwin said that according to the boy's mother, the 3 year old, was at home in Afton with her, and her other 9 year old son.  The mother told Ottawa County Detectives that she was sleeping on the sofa in the living room, when her older son told her that the younger had been accidentally shot.  The children's mother contacted their father who was at home within minutes, and immediately drove the child to the emergency room.

Detectives investigating the case learned from the 9 year old, that he opened a gun safe in the parents' bedroom, by obtaining a key, which was in the room.  The boy told detectives that he was holding the gun, when it accidentally discharged, and struck his little brother.

Ottawa County Sheriff's Department detectives recovered the firearm in question, the empty shell casing, and the bullet, which had traveled through the young victim, through a wall, and into an adjacent room.

“The flight path of the bullet was consistent with the account of the incident given by the 9 year old, “ Derwin said.
....
Sheriff Terry Durborow would like to remind residents with firearms to apprise their children of proper gun safety, and encourages parents and guardians to use gun locks, and to keep firearms and ammunition stored separately.

How about not having guns in the home with children at all?

Every gun in the hands of a child must first pass through the hands of an adult.