A 32-year-old man is being treated as the only suspect in Saturday night's stabbing attack that wounded 11 passengers on a train in Huntington, eastern England, police say.
The other man previously arrested was released after confirmation that he was not involved in the attack.
Initially, nine victims were taken to the hospital in a life-threatening condition. By late Sunday, five of the injured had been discharged from the hospital. Among those still being treated was a member of the train crew who tried to stop the attacker and was in a life-threatening condition, police said.
Counterterrorism police had helped with the initial investigation after the mass stabbing of passengers on a train in eastern England on Saturday, but police later said there was nothing to suggest that the incident was terrorism.
Police originally responded under the codeword "Operation Plato," which is used to denote a response to a "marauding terror attack," but this declaration was later rescinded, The Telegraph reported, citing BTP.
Work is now ongoing to establish the events leading up to the attack and the suspect's background, police said. A knife had also been recovered from the scene.
"Our investigation is moving at pace and we are confident we are not looking for anyone else in connection to the incident," Deputy Chief Constable Stuart Cundy said in a statement.
Police described the sole suspect as a Black British national from Peterborough, 100 miles (160 km) north of London, who had boarded the train there.
The stabbing attack occured after the train left Peterborough station heading south towards London's King Cross.
Large-scale response issued
The East of England Ambulance Service said it mobilized a large-scale response to Huntingdon Railway Station, including numerous ambulances and critical care teams, as well as three air ambulances.
The train was the 6:25 p.m. train from Doncaster to London's King's Cross, BTP confirmed.
Cambridgeshire police said they were called at 7:39 p.m. after reports that multiple people had been stabbed on a London North East Railway (LNER) train.
"Armed officers attended, and the train was stopped at Huntingdon, where two men were arrested. A number of people have been taken to the hospital," the police said in a statement. Over 30 police officers were sent to the scene, Cambridgeshire police confirmed.
LNER issued a "Do Not Travel" notice, and updated that tickets dated for Saturday and Sunday will remain valid up to and including at least Tuesday. Trains on Sunday may be subject to "short-notice cancellation," LNER added.
Eyewitnesses give testimony to the events
Passengers were hiding in train toilets to escape, with witnesses claiming that bystanders were trampled as others tried to flee, according to The Sun.
"There was blood everywhere; it was a terrible scene, really violent. It was like something from a film," a witness told the outlet.
An eyewitness told Sky News that the attacker was a "black male dressed in all-black clothing," and was tasered by police.
Another eyewitness, Olly Foster, told the BBC that he initially heard people shouting "Run! There's a guy literally stabbing everyone," believing it to be a night-after-Halloween prank.
He commented on how he saw an older man "block" the attacker from stabbing a younger girl, which left the man wounded with a gash on his head and neck. Passengers used their clothes to try to reduce the victim's bleeding, he told the BBC.
He also said that while the incident lasted 10-15 minutes, it "felt like forever."
Witness Olly Foster told the BBC that he was on the train heading towards London on Saturday evening when someone ran past him saying a man was stabbing "everyone, everything."
"I put my hand on this chair...and then I look at my hand, and it's covered in blood. And then I look at the chair, and there's blood all over the chair. And then I look ahead and there's blood on all the chairs," he said.
Another witness told Sky News that a suspect was seen waving a large knife before being tasered by police.
Passengers were transferred to buses, which drove them to London, according to the Peterborough Telegraph.
Cambridgeshire Police noted that the A1307 was closed in Huntington town center.
Politicians, officials react to stabbing attack
Prime Minister Keir Starmer posted on X/Twitter that the "appalling incident" was deeply concerning.
"My thoughts are with all those affected, and my thanks go to the emergency services for their response."
"I am deeply saddened to hear about the stabbings in Huntingdon. My thoughts go out to all those affected. Two suspects have been immediately arrested and taken into custody. I am receiving regular updates on the investigation. I urge people to avoid comment and speculation at this early stage," Home Secretary Shabana Mahmood posted.
"My thoughts are with those affected by this shocking incident on a train near Huntingdon. I am getting updates on the situation and we are working closely with the British Transport Police," Transport Secretary Heidi Alexander said.
"I am aware of the incident and am trying to establish further information. My thoughts are with the victims and those involved," Huntington MP Ben Obese-Jecty wrote on X.
"Emergency services (are) starting to move away from the scene, which means it’s becoming more under control, but the two arrests were made at the scene very, very shortly after the incident took place," Obese-Jecty told Sky News.
"When I first arrived here, I had simply never seen as big a response to an emergency incident as there was in terms of police, fire, and ambulance," he added.
"I am aware of an incident involving one of our trains. Our immediate concern is the welfare of our customers and crew on board. My thoughts are with the victims. We are in the process of gathering all the details we can. Further updates will follow as soon as we have more information. Thank you to the emergency services and railway colleagues who are responding to this incident," LNER Managing Director David Horne added.
Knife crime in England and Wales has risen 87% over the past decade, with 54,587 offenses last year alone, a 2% rise from 2023, and among the highest rates in Europe, according to figures from Britain's interior ministry.
Reuters contributed to this report.