Staff continue to be shocked at the brutality of the attack that traumatised a school where care for friends, students and colleagues comes as second nature.
The headteacher spoke for them all after the case when he said: "Everyone is relieved that the episode is now over."
When the boy, now convicted for wounding, started at the secondary school his parents were open with the headteacher about his difficulties.
"We were working with them to help him sort them out," said the head. "He had a superb form tutor and an excellent head of year who regularly had contact with his home and we were doing all we could to support him. But this attack came absolutely from nowhere."
The teenager suffered from Asperger syndrome, but this was not diagnosed until after the attack.
"I don't see it as an inclusion issue," said the head. "That would imply if we knew he had Asperger syndrome then we would not have taken him on. But we do have Asperger children here.
"This school is well-known for coping with individuals with difficulties very effectively.
"We were providing for him and supporting his learning. He had particular needs and we were trying to support him as best we could, as we do with all kids.
"The society in which we live is less secure and more tense than a generation ago and as a school that is something we have to take on board.
Schools need to be prepared, even in sleepy, rural Suffolk.
"Clearly with legal proceedings at an end, it is a significant moment of closure.
"The boy who was stabbed is doing his GCSEs this year. He came back on day one of the September term and apart from the odd absence, which anyone might have, has just got on with it.
"Our priority is to get him up to speed with his GCSEs. He is a very courageous young man and really committed to getting the best GCSEs he can.
Our main role in his rehabilitation has been to support him 150 per cent."