12 year-old boy arrested over 'diagram' of plan to shoot up school

From Columbine to Virginia Tech to the deadly attack that tore apart Oregon's Umpqua Community College earlier this month, students have chosen their own schools as staging grounds for murder and mayhem.

There have been more than 40 such school shootings across America this year. In most cases, the shooter has been a male in his late teens or early to mid 20s.

Now a case in Dallas is breaking that pattern - but for a devastating reason.

On Thursday, Dallas police arrested a student at Trinity Basin Preparatory for allegedly plotting to shoot up the school. The Dallas Police Department said the student had spoken several times over the past month about bringing a gun to school but classmates thought he was joking.

When the student brought a "diagram" of his deadly plan to school on Thursday, a fellow student turned him in.

The possible school shooting plot, though thwarted, has nonetheless shocked people in Dallas due to the suspect's age.

He is just 12 years old.

The pre-teen's alleged plot is all the more stunning because of the apparently meticulous manner in which he allegedly planned the attack.

In a Thursday evening press conference, Dallas Assistant Police Chief Randy Blankenbaker told reporters that the boy had brought to school a "written diagram detailing how the plan would be carried out."

Local TV station WFAA described the diagram as "a detailed map of how he would carry out his attack."

Over the past month, the student had told one of his classmates several times that he planned to shoot up Trinity Basin, a diverse public charter school near downtown Dallas.

The classmate didn't take the 12-year-old suspect seriously - until he showed up with the diagram describing exactly how he planned to open fire in the school.

That's when the classmate told school administrators, who found the diagram in the 12-year-old's hand and contacted police.

Blankenbaker praised the classmate for preventing a possible massacre.

"This young man was very courageous. He did what he needed to do to protect himself and his classmates, and he is to be commended for that," Blankenbaker said, according to NBC 5.

The assistant police chief said the diagram or map was detailed enough to signal serious intent.

"An average person would see this diagram and it could give them grave concern," he said.

"A reasonable person would see this diagram and they would believe that he intended to carry out his threats."

The boy's name has not been released due to his age. He has been charged with exhibition of firearms, a third-degree felony, for the alleged plot even though it's unclear if he actually had access to a weapon.

It's also unclear if he will be charged as an adult. He is currently locked up at the Henry Wade Juvenile Justice Center, according to NBC 5.

The juvenile's arrest was the second such incident in a Dallas-area school in little over a week.

On Oct. 20, a 15-year-old boy was arrested after allegedly threatening to shoot up North Forney High School, according to the Dallas Morning News. The teen reportedly told friends he planned to bring a gun to school the next day.