A TEACHER at the school where two boys had planned the Columbine-style massacre was left stunned when the younger of the pair outlined plans to eliminate students who were "infecting the gene pool".

The conversation happened after the 15-year-old had sent messages about the plot to a friend, who then showed the conversations to teachers in September 2017.

Both boys were interviewed by teachers and, whilst the older boy denied the existence of a plan, his younger classmate made what prosecutors described as "clear and unvarnished confessions".

Giving evidence during the trial, the teacher who had spoken to the teenager, who was 14 at the time, said: "He started off by saying that he had sent the messages because some students were making his life in school intolerable.

"He felt that they needed dealing with severely. He said they needed killing.

"He said he needed to eliminate these people, who were infecting the gene pool."

Describing the conversation as "the most dreadful thing that a student has ever said to me", the teacher added: "He was emotionless about the plan. He seemed to feel that it was something that needed to be done."

The same teacher also claimed he was informed by a police officer that his name was one of several to be listed on a "hit list" of targets that was supposedly drawn up by the teenagers.

During an interview with police following his arrest in October 2017, the younger boy claimed that he believed his co-conspirator was "joking", before saying that he had felt "scared and isolated" as the plan started to get more serious.

In his own police interview, which took place at a similar time, the older boy admitted that he had a "fascination" with the "morbid psychology" of prolific killers.

Discussing a diary in which he outlined these affections, he told officers: "It was an admiration of these killer-type people - you know, when people die and you find their diaries."

When asked about the detailed nature of the plans he had outlined in the journal, he said: "It was just getting stuff out of my head, and they are basically a sort of therapy."