An American woman was killed and five other people injured when a teenager, who police believe was mentally ill, carried out a knife attack in central London on Wednesday, selecting his victims at random in a late-night assault.
A 19-year-old Norwegian national of Somali origin, who has lived in the UK since 2002, was arrested on suspicion of murder at the scene in Russell Square, moments from the British Museum.
The dead woman was named by the Metropolitan police on Thursday night as Darlene Horton, 64. She was the wife of a university professor from Florida who was reportedly hours away from flying home. Florida State University said psychology scholar Richard Wagner was teaching summer classes in London, and his wife had accompanied him to the capital. USA Today said the couple had planned to return to Tallahassee on Thursday.
In a sign of the nervousness about the likelihood of a extremist attack on Britain, Scotland Yard initially said they were considering terrorism as a motive but later rowed back on this suggestion as the mental health history of the suspect emerged.
Speaking outside Scotland Yard’s headquarters, a Met assistant commissioner, Mark Rowley, said there was no evidence that the suspect had been radicalised or was motivated by terrorism.
“While the investigation is not yet complete, all of the work we have done so far increasingly points to this tragic incident as having been triggered by mental health issues,” Rowley said. “Indeed at this time we believe it was a spontaneous attack and the victims were selected at random.”
The Guardian understands the suspect was known to mental health services. It is believed the alleged attacker did not shout words associated with terrorism nor was material found at his address or on electronic devices pointing towards an interest in violent extremism.
He was named by Sky News as Zakaria Bulhan from south London.
In a tribute to the victim, Florida State University’s (FSU) president, John Thrasher, said: “There are no words to express our heartache over this terrible tragedy. We are shocked that such senseless violence has touched our own FSU family and we will do all we can to assist Prof Wagner and his loved ones as well as his friends and colleagues in the psychology department, as they mourn.”
The stabbings – yards from the scene of the 7 July London bus bombing in 2005 – came amid warnings about the likelihood of a terrorist attack in the UK, following a series of incidents across Europe and the Middle East.
But Rowley said officers had interviewed the suspect and his family, had searched addresses in north and south London and had liaised with security services. He said: “I emphasise that so far we’ve found no evidence of radicalisation that would suggest the man in our custody is in any way motivated by terrorism.”
Among the five injured were Australian, American, Israeli and British nationals. Only the British male remained in hospital on Thursday, where he was said to be in a serious but stable condition. The others were released from hospital after being treated for their injuries. The suspect was taken to a south London police station after receiving hospital treatment.
A postmortem is due to be carried out on Horton on Friday.
The 19-year-old was arrested at the scene after police stunned him with a Taser following the attack, which began at 10.30pm near the Imperial Hotel.
Rowley said terrorism was an initial line of inquiry because in the “current climate of threat” and with recent events across Europe, all possibilities should be considered.
Hotel guests described hearing screaming from the square below, while witnesses to the aftermath saw a body lying on the ground as armed police scrambled to the scene on Wednesday night six minutes after the first 999 call was received. Ambulances arrived seven minutes after the first call.
Ellie Cattle, 21, who is staying in a hotel on Bedford Place, off Russell Square, said: “I looked out of my window because I heard sirens. I could see police – three police vans – coming down the road and all I heard was them shouting ‘put it down, put it down’.”
Spanish tourists Anna Calderón and Laura Gómez said they saw one of the victims, a blonde woman in her 20s or 30s, running north up Southampton Row. Gómez said: “We saw a woman with her hand holding her side. She was running and shouting, ‘I need a hospital. I need a hospital.’ A man who looked like he was in his 60s and a woman stopped a taxi and helped her.”
The investigation into the stabbings, understood to have occurred on the eastern side of the square, was being led by murder detectives on Thursday with the support of counter-terrorism officers.
The Met’s commissioner, Sir Bernard Hogan-Howe, said: “My thoughts are with the family of the woman who was murdered and those who were injured. A normal night out in our busy capital has ended in horrific circumstances. Our investigation is moving very quickly and our detectives have been working hard throughout the night. As we have already made clear, mental health remains a substantial focus for our investigation.”
The incident came a day after Hogan-Howe said an undisclosed number of the force’s planned additional 600 armed officers were now fully trained and ready for deployment.
David Cameron, the former prime minister, announced in April that police in England and Wales would train extra firearms officers after a review of armed policing, which was commissioned after the terrorist attacks in Paris in November, when 130 people were killed.
Officers cordoned off the area overnight and were stopping people entering Bedford Place, just off Russell Square, where the suspect is believed to have been arrested. Forensic officers wearing protective suits examined the scene.
Most cordons were lifted on Thursday, with one partial road closure still in place. Witnesses described how armed police arrived in large numbers after the attack and officers established a large cordon to seal off the square, where a forensics tent was later seen.
Additional police were immediately deployed in the area, which is popular with students and tourists. The British Museum, the University of London and University College London are very close by. There are numerous hotels and restaurants in the area, including Hotel Russell and the Imperial.
The mayor of London, Sadiq Khan, called for the public to remain calm and vigilant. The police were doing an incredibly difficult job, the mayor said, adding that the safety of Londoners was his “number one priority”.
