Police are investigating links between a man accused of a mass stabbing on an English train, and a series of other incidents.
British prosecutors have charged Anthony Williams, 32, with 10 counts of attempted murder, one count of assault occasioning actual bodily harm and one count of possession of a bladed article, relating to an incident on a LNER train from Doncaster to London on Saturday.
He has also been charged with another count of attempted murder and possession of a bladed article in connection to an incident at Pontoon Dock station, in east London, earlier on the same day.
Chief Crown Prosecutor Tracy Easton said the Crown Prosecution Service had worked closely with British Transport Police to review a huge volume of evidence, including CCTV.
"Our team of out-of-hours prosecutors worked to establish that there is sufficient evidence to bring the case to trial and it is in the public interest to pursue criminal proceedings," she said.
"The number of charges will be kept under review as this continues to progress.
"We know the devastating impact the events on Saturday's train has had and how the incident shocked the entire country. Our thoughts remain with all those effected."
Mr Williams, a British citizen from the city of Peterborough in eastern England, made a brief appearance at Peterborough Magistrates' Court on Monday.
Flanked by four security officers as he stood in the dock wearing a grey prison tracksuit and handcuffs, he was ordered detained until his next hearing on December 1.
He was not asked to enter pleas.
Police say they are not treating the stabbings as an act of terror.
Williams possibly linked to four further incidents
Mr Williams's court appearance came as police widened their investigation.
On Monday, local time, it emerged the alleged attacker had also been charged with attempted murder and possession of a bladed article after an incident at London Underground station.
Subsequently, Cambridgeshire Police also revealed they were investigating whether three separate incidents in Peterborough, 160 kilometres north of London, were linked to Mr Williams.
A statement from Cambridgeshire Police said authorities were first alerted to reports of a man with a knife at a barber shop on Friday evening.
Authorities were subsequently called again on Saturday morning to reports that the man was still at the scene, but police were unable to locate or identify him after attending.
A third incident occurred on Friday evening, when a man armed with a knife stabbed a 14-year-old boy.
"They were taken to Peterborough City Hospital with minor injuries and were later discharged," Cambridgeshire police said in a statement.
Police were unable to locate the alleged attacker.
"We are currently reviewing all incidents in the time-frame to understand whether there were any further potential offences," the statement said.
"British Transport Police retain primacy for the overall investigation, which will include these three incidents."
'Heroic' railway worker tried to stop train attack
Fear through the train on Saturday as the minutes-long stabbing spree was happening.
Passengers described scenes of panic as bloodied travellers raced down the train to get away from the attacker.
The most seriously wounded victim is a member of railway staff who tried to stop the attacker.
Police called his actions "nothing short of heroic".
He was hospitalised in a critical but stable condition.
The suspect was arrested when the train made an emergency stop in the town of Huntingdon, in eastern England.
ABC, Reuters and AP