Police were questioning a 32-year-old British man Sunday on suspicion of attempted murder over a mass stabbing attack that spread fear and panic on a London-bound train and left 11 people hospitalized.
A second man initially arrested as a suspect was released without charge. Police said they have determined that the 35-year-old was not involved. Police are not treating the stabbings as an act of terror but have not disclosed a possible motive or the type of knife, or knives, used.
Six people remained in hospital on Sunday, one of them in life-threatening condition. Police said he is a member of railway staff who tried to stop the attack and saved many lives with his "heroic" actions. Five other injured people were discharged from hospital.
The men were arrested eight minutes after the first emergency calls were made at 7:42 p.m. Saturday from aboard the train, where passengers had reported scenes of panic and chaos — with many running through the carriages and some seeking safety in the washroom.
"This is a shocking incident, and my thoughts are with those who have been injured and their families," British Transport Police Supt. John Loveless said outside the station in Huntingdon, eastern England, where the train halted soon after the attack.
A train is seen parked at the Huntingdon station on Sunday. (Joe Giddens/PA/The Associated Press)"There is nothing to suggest this is a terrorist incident," Loveless added.
The train made an emergency stop in Huntingdon, a market town located about 120 kilometres north of London. Bloodied and confused passengers spilled out of the train as dozens of police waited, some of them armed.
During the immediate response to the attack, police said that "Plato," the national code word used by police and emergency services when responding to what could be a "marauding terror attack," was initiated. That declaration was later rescinded.
"At this early stage it would not be appropriate to speculate on the causes of the incident," Loveless said.
Belongings of escaping passengers are seen on the ground at the entrance to the Huntingdon train station on Sunday. (Kirsty Wigglesworth/The Associated Press)The attack took place as the 6:25 p.m. train from Doncaster, in northern England, to London's King's Cross station was about halfway through its two-hour journey, having just departed from a stop at Peterborough.
Passenger Olly Foster told the BBC he heard people shouting "run, run, there's a guy literally stabbing everyone," and initially thought it might have been a Halloween prank, as Saturday was the day after Halloween. But as passengers pushed past him to get away, he noticed his hand was covered in blood from a chair he had leaned on.
Following reports that some of those on board the train put themselves in harm's way to protect others, British Home Secretary Shabana Mahmood praised the "exceptional bravery of staff and passengers on the train."
A forensic investigator examines the inside of a train on Sunday. (Kirsty Wigglesworth/The Associated Press)King Charles III said he and his wife, Queen Camilla, sent their sympathies and thoughts to those affected and that they were "truly appalled and shocked to hear of the dreadful knife attack."
London North Eastern Railway, or LNER, which operates the East Coast Mainline services in the U.K., confirmed the incident had happened on one of its trains and said there would be major disruption on the route until Monday.
British Transport Police's Loveless said passengers will see a "high visibility presence of police officers at stations and on trains" on Sunday.