An American man was one of three people stabbed to death in a suspected terrorist attack in a Reading park.

A friend said Joe Ritchie-Bennett, originally from Philadelphia in Pennsylvania, and history teacher James Furlong, 36, who also died in Saturday’s attack, were “great supporters” of the LGBT+ community.

“Their loss is a tragedy to so many people,” Martin Cooper, 36, who is chief executive of LGBT+ charity Reading Pride, told the PA news agency.

“They will be sorely missed by myself personally and many in the community.”

The 25-year-old suspect is understood to be Khairi Saadallah, a refugee of the civil war in Libya who briefly came to the attention of MI5 last year.

Saadallah, who is thought to have been released from prison earlier this month, was tackled to the ground by an unarmed police officer close to the scene at Forbury Gardens on Saturday evening and arrested on suspicion of murder.

He was later re-arrested under Section 41 of the Terrorism Act, which gives powers to hold him without charge for up to 14 days. Police have said they are not looking for anyone else in connection with the attack.

Home Secretary Priti Patel told MPs in the Commons it was “clear that the threat posed by lone actors is growing” as she praised emergency responders, including student police officers.

Conservative MP Chris Loder revealed that one of his parliamentary assistants “ran courageously towards danger” to help injured victims.

He said a member of his staff “not only used his own shirt to stem the bleeding of one victim, but continued resuscitation on a second victim until the paramedics arrived”.

He added: “This was indeed a remarkable and extraordinary effort from a young man who has been with us in Parliament for little over four months and whom I am extremely proud to have as part of the West Dorset Parliamentary team as I hope is the whole House.”

A two-minute silence, attended by more than 100 students, was held at the Holt School in Wokingham on Monday morning in memory of Mr Furlong, who pupils said was “always smiling”.

Ella Banbury, 17, said: “He was just a really kind teacher. You would always see him smile – there wouldn’t be a time where you wouldn’t see him smiling.”

The Philadelphia Inquirer newspaper reported that Mr Furlong’s friend, Mr Ritchie-Bennett, was 39 years old and had moved to England from the US around 15 years ago.

His brother, Robert Ritchie, a captain in the Philadelphia police force, told the paper: “We used to play together every day. We rode bikes together every day. Our family is heartbroken and beside ourselves. He did not deserve to go out like this.”

Mr Ritchie-Bennett’s father, also called Robert, said: “I absolutely love my son with all of my heart and all of my soul.”

Two people injured in the attack remain in hospital, while one has now been discharged.

PA understands from security sources that MI5 had received intelligence that Saadallah planned to travel abroad, possibly for terrorism purposes, but the threat was found to be insubstantial and the information provided did not meet the threshold of investigation.

Former head of UK counter terrorism Sir Mark Rowley told Radio 4’s Today programme that police and security services face a “wicked problem” deciding which of the 40,000 people known to them could launch a terror attack.

The Prime Minister, Boris Johnson, has promised that the Government “will not hesitate” to act if there are changes that could be made to legislation in the wake of Saturday’s events.

Ms Patel told MPs 25 terrorist plots have been foiled since 2017, adding: “The UK’s counter-terrorism strategy remains one of the most comprehensive approaches to countering terrorism in the world.

“But we have all too often seen the results of poisonous extremist ideology. The terrorist threat that we face is complex, diverse and rapidly changing.

“It is clear that the threat posed by lone actors is growing.”

As counter-terror officers investigate, mental health is understood to be considered a major factor in the Reading attack.

The suspect was jailed in October for a string of non-terror offences before his sentence was reduced at the Court of Appeal to a term of 17 months and 20 days.

One of the appeal judges who gave the judgment in March, Mr Justice Goss, noted Saadallah’s various mental health issues, including post-traumatic stress disorder and personality disorder, in reducing the sentence.

The offences included affray, assault by beating, assaulting an emergency worker, criminal damage, having a bladed article and a racially aggravated assault involving a police officer.

The officer described the November 2018 attack as being “the vilest thing she had been subjected to as a police officer” after he spat in her face and called her a “slave” when he was being detained under the Mental Health Act, according to the appeal judgment.

Saadallah was released from prison earlier this month, it is understood, and the Covid-19 pandemic played no part in the decision to free him.

The Sun reported that he left HMP Bullingdon, Oxfordshire, 17 days ago after serving less than half of his sentence.