A bishop in a historically black denomination is urging hundreds of churches to lock their doors during services after police said a white 16-year-old girl collected several kitchen knives as part of a methodically planned attack on black churchgoers.

The plot in north Georgia came to light when Gainesville High School students told administrators the girl had a notebook with detailed plans to ambush worshippers at predominantly black Bethel African Methodist Episcopal Church, police said.

Her plan was to attack a small group as they worshipped, Gainesville Police Chief Jay Parrish told reporters. He said he believes she wanted to gain notoriety.

Bethel is in the same denomination as Emanuel AME Church in Charleston, South Carolina, where a 2015 mass shooting left nine black church members dead. That denominational link played a role in the Georgia investigation, Gainesville police Cpl. Jessica Van said Wednesday.

A prominent church leader also took note of it.

“I do have a concern that AME churches are being targeted,” said Bishop Reginald Jackson, whose district includes the Gainesville church.

Jackson on Wednesday was preparing to send memos to the more than 500 AME congregations in Georgia with one recommendation that reflects the heightened threats of the times: “When they start the service, they need to make sure that all the doors are locked,” he said.

He said he plans to send similar messages to other AME bishops across the country, urging them to enhance security.

AME churches may draw the ire of white supremacists not only because of their demographics, but also because their leaders have traditionally been outspoken on social justice issues, Jackson said. Those strong stands can put them at odds with extremists.

At St. James African Methodist Episcopal Church in Erie, Pennsylvania, the doors are locked after worship starts on Sunday mornings, the Rev. Dale Snyder Sr. told The Erie Times-News earlier this year.

“We just can’t afford to have people come here and shoot us all up,” he said.

The South has a long history of black church bombings, arsons, shootings.

In South Carolina, white supremacist Dylann Roof was convicted of killing the nine black church members during their Bible study lesson at the Charleston church. Roof later told FBI agents he had hoped the killings would start a race war. He has been sentenced to death.

In Louisiana, the white son of a sheriff’s deputy was arrested in April and accused of a setting fires that destroyed three black churches in rural Louisiana. Holden Matthews is awaiting trial on arson and hate crimes charges in the Louisiana church burnings.

When the Louisiana churches burned, it prompted security changes halfway across the country at Bethel African Methodist Episcopal Church in Cedar Rapids, Iowa.

The side entrance of the Iowa church is kept locked on Sunday, and volunteers monitor the front entrance, The Gazette reported this year. When the service starts, they remain on “high alert,” the Rev. Leoma Leigh-Williams told the newspaper.

The north Georgia teen, whose name hasn’t been released, had done a significant amount of internet research while planning the attack, Parrish said. He told WSB-TV he believes she might have been “radicalized” on the Internet.

“Our investigation indicated the church was targeted by the juvenile based on the racial demographic of the church members,” Parrish said Tuesday.

The girl is charged with criminal attempt to commit murder and is being held in a youth detention center in Gainesville, about 50 miles (80 kilometers) northeast of Atlanta.