A group of schoolchildren aged between 8 and 10 have been arrested for hatching a plot to attack their teacher, handcuff her and then possibly use a serrated steak knife to inflict serious injury.

The pupils are said to have been angry with their teacher for telling off a member of their class who was caught standing on a chair.

The alleged plot, which involved as many as nine boys and girls at Center Elementary School in Waycross, Georgia, had been laid carefully over the course of a week: one child’s job was to cover windows so that no one would see them, while another was supposed to clean up after the attack.

Tony Tanner, the chief of police, said that the children apparently planned to knock the teacher unconscious with a glass paperweight, bind her with handcuffs, put duct tape over her mouth and then stab her with the knife. “It was a rather elaborate scheme for children of that age,” he acknowledged. “We did not hear anybody say they intended to kill her, but could they have accidentally killed her? Absolutely. We feel like if they weren’t interrupted, there would have been an attempt.”

Mr Tanner was similarly uncertain as to how many of the children took the scheme seriously. One boy in the group decided against smuggling a toy or replica gun into school — apparently because he feared that he would get into trouble.

Police were called in after another pupil told a teacher that a girl had taken a weapon to school. The purported target of their planned attack, Belle Carter, is a veteran teacher of children with learning disabilities.

Two girls aged 9 and a boy aged 8 have been charged with conspiracy to commit aggravated assault. They, along with half a dozen other third-grade pupils, have also been disciplined by the school or given suspensions. The children are all too young to be prosecuted in adult courts, and probably too young to be sentenced to a youth detention centre. Mr Tanner said that their parents were “shocked, saddened and surprised — this is their worst nightmare”.

Ms Carter is said to have told detectives that the children were not known as troublemakers. Theresa Martin, spokeswoman for the Ware County school system in southern Georgia, said: “From what I understand, they were considered pretty good kids.” Angie Coleman, the school principal, said: “This is an isolated incident.”

It was reported yesterday that at another school in Georgia — this time in Dawson — a group of 11 and 12-year-olds had been charged with aggravated assault on their teacher after putting the painkiller, Tylenol, in her drink to make her sick.

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