Two Georgia teenagers appeared in court Thursday on charges that they planned to attack their high school.

Alfred Dupree and Victoria McCurley, who were arrested Wednesday, face several charges including attempted murder and making terroristic threats, according to a statement from the Cherokee County Sheriff’s Office. Both are 17 but are being charged as adults.

A judge denied bond for both suspects at an initial hearing Thursday afternoon. Police said the investigation remains open and ongoing. Neither Dupree nor McCurley has entered a plea.

Police said Wednesday they were informed of the threat by campus police officers at Etowah High School in Woodstock, Georgia, about 20 miles northwest of Atlanta.

Campus police were originally tipped off by someone who had become aware of “suspicious statements that had been made” indicating a potential threat.

Asked about the seriousness of the threat, Sgt. Marianne Kelley, spokeswoman for the sheriff’s office, told reporters Wednesday, “We assessed that it was definitely something that could have been moved forward with,” hence the serious charges.

Diary detailed plans

Authorities went to Dupree’s home Wednesday evening and spoke with the 17-year-old and his parents, Kelley told CNN Thursday.

Investigators were provided with Dupree’s personal diary, Kelley said, which outlined alleged threats to the school and specific staff members and students, as well as the intention to carry out an attack.

Over the course of the investigation, police became aware of McCurley’s involvement, and search warrants were executed at both students’ homes.

It was at McCurley’s home that police found what was described as an “incendiary device,” and an “undetermined powder substance,” Kelley said in a news conference Wednesday. Both of the items were sent to the Georgia Bureau of Investigation for further testing to “determine the chemical make up.”

The people whose names were listed in the diary have been made aware of the fact their names were included in the diary, Kelley said.

The diary did not provide investigators with a tentative timeline for when an attack might occur, police said.

Firearms were not believed to be involved in the attack, but a family member did voluntarily turn over some weapons for safekeeping, Kelley told CNN, but “not for evidentiary purposes.”

Sheriff Frank Reynolds said in a press conference Thursday afternoon that he spoke to one of the detectives involved, who “indicated this would have been a Columbine-type incident in his opinion, and that’s why the severity of the charges and so forth.”

“I think there was an imminent threat,” Reynolds said, “only for the fact that they had detailed plans of what they wanted to do and how they wanted to carry it out.”

Principal reassures parents

“The Cherokee Sheriff’s Office wants to make sure that parents and families understand that we take this very seriously,” Kelley said Wednesday. “We don’t want anything to happen to students in our county, or in our community. We will do anything to protect them.”

Etowah High School Principal Robert Horn informed parents of the situation in a letter sent home Wednesday, emphasizing that there are no additional threats to the school.

“We will not tolerate violence of any kind at our schools,” the Cherokee County School District said in a statement.

“We take all threats to the safety and security of our students and employees very seriously. Anyone with information about threats is asked to immediately report it to police.”

The arrest warrants for both suspects have been sealed by a judge. It was not clear Thursday morning if the suspects were represented by attorneys.