The Libyan suspect was on MI5 list after he joint terrorist group back GNA

The suspect in an alleged terror attack that left a teacher and two others dead was known to security services and other authorities, it emerged on Sunday.

Khairi Saadallah, 25, was put on the security service’s ‘radar’ less than a year before Saturday's attack after a tip-off that he planned to travel to his native Libya where it was feared he wanted to join a militant jihadist group.

But the file was closed after two months when intelligence services found no credible evidence to support the claim.

Questions remain over whether Saadallah should have been at large at the time of Saturday evening’s attack in a park in Reading, Berks, after being released early from prison this month for minor, non-terrorist offences.

It has also emerged that Saadallah, who it is understood had serious mental health problems, had come to the UK as an illegal immigrant in 2012 but was granted asylum in 2018.

He had boasted to friends in the UK that he had fought as a child soldier to overthrow Colonel Muammar Gaddafi.

He was under investigation as a person who might travel abroad “for extremist reasons”, but sources indicated that the inquiry was closed relatively quickly without any action taken as no genuine threat or immediate risk was identified. Intelligence agencies believe Saadallah had mental health problems, the sources said.

There was no immediate evidence that the Reading attack was underpinned by an allegiance to Islamic State or al-Qaida, although investigations are ongoing. Police said they believed the attacker was acting alone.

Boris Johnson hinted at a fresh crackdown on terror suspects when he said the government was ready to act on any lessons that emerge from the tragedy. The prime minister and other leading public figures condemned the violence and expressed condolences to victims’ relatives.

Among the three people killed in the attack shortly before 7pm in Forbury Gardens was a 36-year-old local secondary school teacher, James Furlong. On Sunday evening his parents, Gary and Janet, paid tribute to “a wonderful man … beautiful, intelligent, honest and fun … the best son, brother, uncle and partner you could wish for”.

Furlong was head of history, government and politics at Holt school in Wokingham, near Reading. Colleagues and pupils’ parents described him as “passionate”, “gentle” and “caring”.

The school wrote to pupils’ families to notify them that the teacher had been caught up in the attack. The letter described him as a “very kind and gentle man” with a “real sense of duty and care for each and every one of our students”. Lessons on Monday have been cancelled for all year groups, with counsellors on site for students and staff to seek support.

Three other people were injured in the attack, which lasted less than five minutes. Two were taken to hospital, with one later discharged and the other described on Sunday as stable.

Saadallah was initially arrested on suspicion of murder, with police not treating the incident as terrorism, but he has now been rearrested under Section 41 of the Terrorism Act 2000, giving police greater powers of detention.

Witnesses described horrific scenes as a knife-wielding attacker stabbed people in the park, which is popular with families, especially amid coronavirus lockdown measures. Thames Valley police said they had detained and arrested the suspect within five minutes of the first call at 6.56pm.

As the police investigation continued on Sunday, it emerged Saadallah, who was granted asylum in the UK, was previously on the radar of the security services. He is also understood to have served prison sentences for relatively minor offences not related to terrorism.

The head of counter-terrorism policing, Metropolitan police assistant commissioner Neil Basu, sought to reassure the public that the attack was an isolated attack, with no accomplices being looked for.

He said: “From our inquiries so far, officers have found nothing to suggest that there was anyone else involved in this attack and presently we are not looking for anyone else in relation to this incident.

“Although the motivation for this horrific act is far from certain, counterterrorism policing have taken responsibility for leading the investigation.”

There were many witnesses to the attacks, which took place in the central Reading park which is home of the Maiwand Lion statue, the image of which has been adopted by Reading football club and the Reading Post newspaper.

A police officer is said to have tackled the suspected attacker to the ground while bystanders attempted to give CPR before paramedics arrived.