16-year-old girl had 'detailed plan to commit murder' at predominantly black church: Police Other students found a notebook with "detailed plans," police said.

A 16-year-old girl was arrested over her "detailed plan to commit murder" at a predominately black church in Georgia, police said Tuesday.

The teenager, who is white, was charged with criminal attempt to commit murder regarding the alleged plot at Bethel African Methodist Episcopal Church, according to a statement from the Gainesville Police Department.

Police did not reveal details of the plan, but said the church had been "targeted by the juvenile based on the racial demographic of the church members."

School administrators were the ones first notified of the alleged attack after other students found the teenager's notebook that laid out the plot, prompting them to contact school counselors at Gainesville High School, according to police.

The school conducted a preliminary investigation and were able to verify the threat, police said. The investigation was then turned over to Gainesville police.

Dr. Jeremy Williams, superintendent of Gainesville City School System, said he was "stunned" over the arrest.

"A single act by a student does not represent the views and beliefs of Gainesville City School System. As a school system that celebrates our diversity, we are beyond stunned with the recent development," Williams said in a statement to ABC News. "However, we are extremely proud of our students notifying school administration of a possible off-campus threat."

The church was notified and police said the threat was under control. The church did not immediately respond to ABC News for comment.

Gainesville Police Chief Jay Parrish applauded the students and school administration for helping stop "a potentially horrific incident."

The teenager was transported to the Regional Youth Detention Center.