A man is being hailed as a hero after intervening during a mass stabbing incident, an act which police assert “saved lives.” Unfortunately, this brave staff member is now in critical condition, one of the 11 individuals who were hospitalized following the tragedy.

Despite the severity of the attack, authorities have not yet filed charges. However, they do have one man in custody as the investigation continues.

Here’s a comprehensive look at the events that unfolded.

The incident occurred at approximately 7:42 PM local time on a Saturday evening, which corresponds to 6:42 AM AEDT the following day. Passengers aboard a train traveling from Doncaster to London urgently contacted the police, reporting chaos as people desperately fled from the attacker. Many sought refuge in the train’s toilets as they attempted to protect themselves.

The situation was further controlled by the quick thinking of the train driver, a war veteran, who executed an emergency stop at Huntingdon, a location about 120 kilometers north of London. His decisive action likely prevented further harm and allowed emergency responders to reach the scene more swiftly.

The train driver, since identified as a war veteran, pulled the train in to an emergency stop at Huntingdon, about 120km north of London.

Police swarmed the train and arrested two men at about 7.50pm local time, just eight minutes after the first emergency calls.

Ten people were taken to hospital, while an 11th later self-reported.

In their initial response, police treated the mass stabbing as a potential terror incident, broadcasting the code-word “Plato” to responding officers – the term used to indicate a “marauding terror attack”.

However, authorities have since walked that back, without speculating further as to motive.

“This is a shocking incident and my thoughts are with those who have been injured and their families,” British Transport Police Superintendent John Loveless said outside the station in Huntingdon in eastern England where the train halted soon after the attack.

“There is nothing to suggest this is a terrorist incident.”

How are the victims?

Six people remain in hospital as of this morning (AEDT), with one in a critical condition.

That person has been identified as a railway staffer who tried to stop the attack, and who police say saved lives with his “heroic” actions.

“Having viewed the CCTV from the train, the actions of the member of rail staff were nothing short of heroic and undoubtedly saved people’s lives,” Deputy Chief Constable Stuart Cundy said.

Five other people have been discharged from hospital.

Who were the men arrested?

A 32-year-old man and a 35-year-old man were both taken into custody at the scene.

However, this morning, police confirmed they had released the 35-year-old man without charge, saying he had not been involved.

“It was reported in good faith to officers responding to the incident that he was involved in the attack, and following enquiries we can confirm that he was not involved,” police said in a release.

The 32-year-old remains in custody.

He has been identified as a British national from Peterbough, which is where police say he boarded the train.

A knife has also been recovered at the scene.

It is likely the sole remaining suspect will be charged once police have finished their interrogation.

London North Eastern Railway, or LNER, which operates the East Coast Mainline services in the UK, confirmed the incident had happened on one of its trains and said there would be major disruption on the route until Monday local time (Monday evening/overnight AEDT).

Loveless said passengers will see a “high visibility presence of police officers at stations and on trains” on Sunday.

Reported with additional details from Associated Press.