ATLANTA -- A frustrated mother came forward, Friday, to raise questions about the investigation into her son.

The McNair Middle School student is accused of bringing a gun and ammo to school just weeks after threatening to kill a teacher. According to police, the seventh grader, a kid at just 12 years old, had a 10 mm handgun and more than a dozen bullets in his backpack.

"I want to know where did he get that gun from," the mother said. "I was with my son that morning - we walked the dog. His book bag had pencils and paper in it."

She believes someone else put the gun in his bag. Whether he was framed or involved in something illegal, she doesn't know. But she said parent's should be concerned.

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"These guns are so easily accessible by our seventh graders, our middle schoolers, our babies," she said. "Because he's still baby. It was too easy for that gun to get into that school. I know for a fact that my son did not bring it to that school."

And she does not believe he intended to harm anyone with it. About a month before the gun incident, a McNair Choir teacher said the same student threatened to kill him.

But his mother said her son has been threatened by another student with a gun on campus and has been bullied by administrators at the school. She provided a letter, written in December, trying to get help from the district. She said they never responded.

"The school is unsafe, period," she said.

The boy's mother told 11Alive that the family doesn't own any guns and her son doesn't have an allowance so there's no way he could buy one.

As of Friday night, he remained in juvenile detention and could be expelled from school.