Armed police officers were called to Thorpe St Andrew School after a teenage girl was stabbed by another pupil
Warning: The following report contains details that some may find distressing
The father of a teenager who tried to kill a fellow pupil in a school knife attack has described his devastation and belief that his son was "radicalised" by extreme material online.
The boy, now 16, was found guilty of attempted murder last week after a trial heard how he harboured a hatred of women, had a fascination with serial killers and had planned to target others in the attack at Thorpe St Andrew School, near Norwich.
Speaking exclusively to the BBC and calling for tighter controls, the boy's father said he did not want to "absolve" his son but suggested online material and "a culture of violence and horror" had influenced him.
The government said it was committed to ensuring all children were safe from radicalisation and threats online, pointing to its Prevent anti-terrorism scheme and the Online Safety Act, which compels social media platforms to remove and prevent the spread of illegal content.
The boy cannot be identified due to his age, and nor can witnesses and the victim in the case.
His father, who we are calling John, apologised to the 15-year-old girl injured in the attack on 11 March, saying: "We're so very sorry for what happened."
John spoke of his fears that young men were being radicalised towards violence and hatred.
"You can think... it can never happen to my family or my son couldn't be involved, but that's what we thought and that wasn't the case," he said.
John's son was convicted after a trial at King's Lynn Crown Court
A two-week trial at King's Lynn Crown Court heard how the boy dressed in black and wore a face mask to stab the girl with a kitchen knife.
John described his own "rising feeling of panic" on the day of the attack.
He said he and his wife had been "fearful for what he might have done and fearful for what would happen to him".
But John said he only learned the full details when they emerged during the trial.
He acknowledged the attack would have had "major repercussions" for the victim, who spent a night in hospital but was not seriously injured.
"I hope the victim and her family can sort of get over it as soon as possible in terms of healing and move on," he said.
Roads around the school were cordoned off following the attack
Before the attack, John said, his family had been "normal".
His son was shy but had a group of friends and had been "kind and thoughtful" at home.
As a teenager, he began to spend more time on his own, but John saw nothing concerning.
However, police later found the boy had searched the internet for material on mass shootings and serial killers, including on the night before the attack - something John said he had "no idea" about.
"It was shocking and devastating that he would have been looking at that kind of stuff," he said.
While there were parental controls on his son's devices, these were mainly to limit screen time.
"There was nothing to indicate that anything sinister was going on," said John.
If you have been affected by any of the issues raised in this story, you can visit the BBC Action Line for information and support
Asked if they should have known more about what was on their son's phone, he said: "I can see the argument.
"I doubt many parents will go through their kids' browsing history on a regular basis.
The kitchen knife used to stab the victim had a blade measuring 18cm (7in) and a handle measuring 12cm (5in) and was found in a wooded area
When police searched the family home after the attack, they found the boy had written notes planning a wider attack.
They talked about deaths and injuries, listing misanthropy, misogyny, suicide, bullying as motives.
John said reading the notes made him feel "physically sick".
"It's still perplexing to us that he would write those things and feel those things that he was feeling," he said.
"He just seems like a different person doing that; some different version of him that's emerged from whatever he's been watching or seeing online."
John said his son had told him he believed his interest in extreme violence began after he saw a clip on TikTok from TV drama Dexter, which tells the story of a vigilante serial killer.
"Once you watch one thing like that, the algorithm, of course, feeds you more of the same content," he said.
He said he believed some young men could be drawn towards increasingly extreme material online and called for tighter regulations on children's access to it.
"There's the radicalisation of young men in particular. They talk about it with regards to terrorism and political ideology, but [there's] a radicalisation towards violence and hatred," he said.
"There must be ways to block content or to monitor content. We see millions of pounds spent on other things. Is there enough being spent on this kind of thing?"
Ofcom, the official regulator for broadcasting and the internet, says it is the responsibility of tech firms to keep children safe online.
It says it is holding those companies to account, but has the following tips for parents, external:
Talk regularly to your children about what they do when they're online.
Make sure your children register with online services using their real age, to help prevent them from accessing content that is only suitable for people who are older.
Make sure they know how to report inappropriate or harmful content, how to block accounts that share it and encourage them not to share it themselves. If content is illegal, report it to the police.
Parental controls are a useful tool, helping you to monitor and limit the time your children spend online, and what they do when they're there.
John acknowledged parallels with his son's crime and the storyline of award-winning drama Adolescence starring Owen Cooper (left) and Stephen Graham
The attack by John's son had parallels with the storyline of hit Netflix drama Adolescence, which shows the aftermath of the fatal stabbing of a teenage girl by a fellow school pupil.
It highlighted the corrosive impact of social media and misogynist influencers on some teenage boys and prompted then Prime Minister Sir Keir Starmer to pledge to tackle the issue.
John said while he had not personally watched the show, he was aware of discussion around it and could see why links to it might be made.
"Knowing what it was about did prompt a chat with our son about the manosphere and those sort of toxic influencers it references," he said.
