Waycross, Ga. ? A group of third-graders plotted to attack their teacher, bringing a broken steak knife, handcuffs, duct tape and other items for the job and assigning children tasks including covering the windows and cleaning up afterward, police said Tuesday.

The plot involving as many as nine boys and girls at Center Elementary School in south Georgia was a serious threat, Waycross Police Chief Tony Tanner said.

School officials alerted police Friday after a pupil tipped off a teacher that a girl had brought a weapon to school. Tanner said the students apparently planned to knock the teacher unconscious with a crystal paperweight, bind her with the handcuffs and tape and then stab her with the knife.

“We did not hear anybody say they intended to kill her, but could they have accidentally killed her? Absolutely,” Tanner said. “We feel like if they weren’t interrupted, there would have been an attempt.”

The children, ages 8 to 10, were apparently mad at the teacher because she had scolded one of them for standing on a chair, Tanner said.

Two of the students were arrested on juvenile charges Tuesday and a third arrest was expected. District Attorney Rick Currie said other students told investigators they didn’t take the plot seriously or insisted they had decided not to participate.

Currie said he decided to seek juvenile charges against two girls, ages 9 and 10, who brought the knife and paperweight and an 8-year-old boy who brought tape. He said all three students faced charges of conspiracy to commit aggravated assault, and both girls were being charged with bringing weapons to school.

The purported target is a veteran educator who teaches third-grade students with learning disabilities, including attention deficit disorder, delayed development and hyperactivity.