A knifeman who stabbed a teenage boy on a Docklands Light Railway (DLR) train in London appeared to believe his victim was the devil, a court has heard.
Anthony Williams, 33, denies attempting to murder Isaiah Idris, who was 17 at the time, on a DLR train heading to Pontoon Dock station in the early hours of November 1 last year.
He also denies the attempted murders of three people in Peterborough on October 31, and of 10 people on an LNER train from Doncaster to London on November 1 last year. The LNER service had to make an emergency stop in Huntingdon, Cambridgeshire.
Williams is standing trial at Cambridge Crown Court, facing a total of 14 counts of attempted murder.
Witness describes attack on DLR train
Witness Macarena Lopez, who was on the DLR train travelling home from a Halloween dinner with friends, told police that a man on the train "started to be loud" and was "brandishing a knife".
In a video-recorded interview played to jurors, she said the man appeared to be "specifically targeting a boy who seemed to me like a teenager, maybe 18 or so, maybe a bit younger, who was with a girl next to him".
She said the man "fixated on the boy and started saying: 'You are the devil' or 'You are the demon'".
Ms Lopez said she thought the man may have been having a "psychotic episode" and "was seeing things that were not clear to the rest of us".
"The attacker for some reason he thought this boy was the devil and wanted to harm him," she said.
Court hears of injuries and reaction
The court previously heard Williams cut Mr Idris, now aged 18, on the face and hand as he tried to block his attacker.
Ms Lopez continued: "I remember hyperventilating a lot and really hoping he didn't do any more harm, as it was so unpredictable, it was so senseless, there was no story to it."
She said that a "middle-aged man next to the boy started confronting the attacker".
Williams got off the train when it arrived at Pontoon Dock station.
"It's almost like by magic his brain just switched off, that psychotic mind just calmed down as he just left the station as soon as he could," Ms Lopez said.
Judge Mr Justice Calver earlier told jurors at Cambridge Crown Court that there was no dispute that Williams had carried out the attacks, but they must consider whether he intended to kill the individuals when he attacked them.
In a video interview played to jurors earlier in the trial, Mr Idris told police that he remembered Williams, whom he did not know, saying: "Are you beefing with the devil?"
