Anthony Williams, 32, has been charged with 10 counts of attempted murder after multiple people were stabbed on a service between Doncaster and London on Saturday evening.
He has also been charged with another count of attempted murder in relation to a stabbing that took place in London in the early hours of Saturday morning.
Police are now investigating whether Williams could be the suspect in three other incidents, the first of which took place just over 24 hours before the train attack.
7.10pm, Friday: Peterborough city centre stabbing
The first of the incidents police are investigating is a stabbing that took place on Friday evening.
A 14-year-old was taken to hospital after being stabbed by a man with a knife in Peterborough city centre, Cambridgeshire Police said.
The force added that the offender had left the scene when the authorities were called and was not be found in a search of the area.
7.25pm, Friday: Man seen with a knife in Fletton, Peterborough
A man with a knife was then seen at a barbers in the Fletton area, 15 minutes after the stabbing.
This incident was not reported to the police until two hours after it occurred.
The force said it did not send officers to the scene as the man was no longer there and had not returned.
12.46am, Saturday: London knife attack
Williams has been charged with one count of attempted murder and possession of a bladed article in connection with an incident on a London train in the early hours of Saturday, British Transport Police (BTP) said.
A victim suffered facial injuries after being attacked with a knife on a Docklands Light Railway train at Pontoon Dock station, east London.
BTP said the suspect had left the location before police arrived, and that officers subsequently identified Williams as a suspect.
9.25am, Saturday: Man seen with a knife again in Fletton
The barbers in Fletton contacted the police again on Saturday morning, while a man with a knife was at the scene.
Cambridgeshire Police said officers were sent to the location and arrived within 18 minutes. They searched the area but were unable to locate or identify the man.
Read more from Sky News:
Air India crash survivor speaks to Sky News
Pregnant British teen freed from Georgia jail
Four injured as train derails
7.42pm, Saturday: Huntingdon train knife attack
Police were called to reports of a multiple stabbing on board a service from Doncaster to London’s King’s Cross.
The attack is understood to have begun shortly after the train left Peterborough and passengers pulled the emergency alarms to alert the driver, who diverted the train to Huntingdon, Cambridgeshire.
Armed police were deployed to Huntingdon station, where the LNER train was stopped and Williams was detained within eight minutes of the first 999 call.
Footage of his arrest has emerged, showing a man on the ground surrounded by officers and a barking police dog, with the sound of a Taser being deployed.
Another man was also detained but later released after officers established he was not involved.
Williams is due to appear at Cambridge Crown Court on 1 December.
