A 13-year-old suspected of stabbing two children at a school in London was arrested after being seen acting “distressed” at a mosque, police have said.
The Metropolitan Police’s Counter Terrorism unit is leading the investigation after the two boys, aged 12 and 13, were injured at Kingsbury High School in Brent on Tuesday.
Speaking at a media briefing on Wednesday afternoon, Detective Chief Superintendent Helen Flanagan said she believed the suspect, who was a former pupil, arrived at the school at around 12.30pm, before entering a first-floor classroom where he allegedly sprayed a pupil with a non-noxious substance.
She added: “The suspect has then attacked another pupil, a 13-year-old, in that classroom, stabbing him, and then the suspect left, running down the hallway of the school and the stairs.
“As he was leaving, he then attacks another victim, a 12-year-old, stabbing him before running off and away from the school.”
After a manhunt was launched, she said, the force received a call from a member of the public concerned over a child appearing “distressed” at a mosque in northwest London.
Officers then arrested a 13-year-old, a British national, on suspicion of attempted murder in the vicinity of the mosque at 4.50pm. He remains in custody as officers try to establish the motive for the attack, which is not being treated as a terrorist incident at this stage.

The boy had no link with the mosque and police believe it is a coincidence that he was there, Det Chf Supt Flanagan said.
In the update, she also said the two boys stabbed did not “thankfully” suffer life-threatening injuries, and remain in hospital in a stable condition. The boy sprayed with a substance did not suffer any injury, she said, but is being treated as a victim in the case.
Police have searched three premises and are interviewing 30 to 40 witnesses to the stabbing as part of the investigation, she added.
She said: “At this point, we do not believe the suspect to have any particular connection to that mosque, and at this stage, we think that it may have been coincidental that he ended up in that area, and all of those at the mosque have been incredibly supportive of this investigation.”
Earlier on Wednesday, Sir Keir Starmer called the stabbing “an appalling attack” during Prime Minister’s Questions.

Schools minister Georgia Gould also told Sky News that the government could look at bolstering security in schools in the wake of the stabbing, but ruled out installing metal detectors.
The headteacher of the school said the incident was “a deeply traumatic event for the whole school community” in a letter to parents and carers.
Alex Thomas said: “I fully appreciate that this will be very upsetting news to hear and, as you can imagine, this has been a deeply traumatic event for the whole school community.
“The situation is under control, but a live investigation is taking place. We are working closely with the authorities and I will provide further updates as soon as I am able to share confirmed information.”
Simon Theodorou, a parent of a child at the school, told The Telegraph that the attacker “managed to get his way in by climbing over a wall”. He also claimed one of the victims “pulled the fire alarm to get help”, praising the boy as a “hero”.

Pupils were spoken to by police officers in one of the school’s halls for more than three hours after the usual school day finished on Tuesday – and some were seen leaving in tears.
The father of one pupil said children were obviously “traumatised by what happened in front of them”.
At Wednesday afternoon’s police briefing, Detective Chief Superintendent Luke Williams said he understood that the incident had been “hugely distressing” for the local community.
He said: “It’s hard to imagine the impact on the loved ones of the victims and the officers are providing them with special support. I hope the knowledge this was an extraordinary one-off event, which led to the swift arrest of the suspect, provides some reassurance.”
Home secretary Shabana Mahmood said her thoughts and prayers were with the two children stabbed in the “shocking attack”.
Mayor of London Sir Sadiq Khan urged anyone with information to contact the police, adding: “There is no honour in staying silent. This awful violence has absolutely no place in our city.”