LOUISIANA (REUTERS) - An 8-year-old Louisiana boy who shot and killed his elderly grandmother after playing a violent video game told authorities "he thought it was a toy gun,"

The boy, whose name was not disclosed, is not charged with a crime and has been released to his parents. Louisiana law prevents children under 10 from facing criminal charges, on the assumption that they are not mature enough to have criminal intent, said East Feliciana Parish District Attorney Samuel D'Aquilla.

The boy did not appear to have murder in mind when he pointed the handgun at the back of 87-year-old Marie Smothers' head and pulled the trigger last week, Mr D'Aquilla said.

"He doesn't know that if you point a gun at somebody, it kills them and they're gone forever," Mr D'Aquilla said. "It's not because he is a cold-blooded killer and he did this to kill his grandmother."

He said the boy was "really shaken up" by what happened.

The shooting happened last Thursday evening in Slaughter, Louisiana, authorities said.

Police had initially said the boy intentionally shot his grandmother as she sat in her living room, and noted in their report that the boy had just finished playing the violent video game "Grand Theft Auto IV."

On Tuesday, Mr D'Aquilla said it was "very difficult" for prosecutors to say the boy wanted his grandmother dead.

"Whether you can link it back to Grand Theft Auto, I don't know," he said. "In my mind, I would say it's something the kids don't need to be seeing because it distorts reality."

Take-Two Interactive Software Inc, whose Rockstar Games studio develops the Grand Theft Auto games, said in a statement on Monday that it was shocked by the shooting.

The company said the event "emphasizes the urgent need for America to address the availability of dangerous weapons to people who obviously shouldn't have access to them".