A review into the case of two teenagers who planned a Columbine-style school massacre has recommended action to support vulnerable pupils.
Thomas Wyllie and Alex Bolland, both 14 when arrested in 2017, planned to shoot and kill pupils and teachers at school in Northallerton, North Yorkshire.
The pair were given 10 and 12-year custodial sentences for conspiracy to murder in 2018.
The review said action should be taken to tackle bullying.
Wyllie and Bolland had drawn up a "hit-list" of targets at the school who they believed had bullied and wronged them, their trial was told.
North Yorkshire Safeguarding Children Partnership said fresh guidelines and training to identify and intervene earlier in coercive relationships between children were necessary.
It follows a two-year investigation into the teenagers' plot to replicate the US shooting in which 13 people and two gunmen were killed at Colorado's Columbine High School in 1999.
The report focuses on how information was shared between different agencies and responses to incidents reported prior to the boys' arrests.
The school cannot be identified due to a court ruling and the report has not been published.
Parents of former pupils at the school described the decision not to publish as "disappointing", the Local Democracy Reporting Service said.
The safeguarding partnership said it contained "highly sensitive details and personal information relating to a number of young people who would be identifiable from the information within the report".
The partnership, including the county council, North Yorkshire Police, the NHS, schools and community groups, said many of its recommendations had already been acted on.
It said "a great deal of work" had taken place with schools to support vulnerable pupils, tackle bullying and support victims.
Dr Maggie Atkinson, chair of the partnership executive and former children's commissioner for England, said the case had been "complex and tragic".
Dr Atkinson added she was clear the review's findings and recommendations "have been - and continue to be - acted upon to strengthen existing professional practice".