Tooting teenager and former Graveney School pupil Zakaria Bulhan, 19, named as man suspected of stabbing American woman Darlene Horton to death in Russell Square, central London

The 19-year-old former Graveney School pupil was arrested yesterday on suspicion of murdering the woman before going on a stabbing rampage and injuring five others in Russell Square at about 10.30pm on Wednesday.

Pic: Zakaria Bulhan, in his school days

The stabbings came just days after the Met Police announced it would be putting more armed officers on the streets.

Mr Bulhan was confirmed by the Met Police to be a Norwegian national of Somali origin.

Officers reportedly raided a flat in Tooting yesterday, where it is believed Mr Bulhan lived with his family.

Pic: The flat believed to be home to Zakaria Bulhan, raided by police. SWNS.

The victim in the stabbing has now been named as 64-year-old American national Darlene Horton, from Florida.

The Met has since ruled out the possibility the attacker was radicalised, having at first said it is “keeping an open mind” about the possibility of terrorism.

Standing outside Scotland Yard, assistant commissioner Mark Rowley said yesterday: “Whilst the investigation is not yet complete - all of the work that we have done so far, increasingly points to this tragic incident as having been triggered by mental health issues.

“At this time we believe this was a spontaneous attack and the victims were selected at random.

“So far we have found no evidence of radicalization or anything that would suggest the man in our custody was motivated by terrorism.”

A British man, who was stabbed in his stomach during the attack, remains in hospital, where his condition is described as serious but stable.

An American man, Australian woman, Australian man and Israeli woman have since been discharged from hospital having suffered stab wounds.

Numerous people have taken to social media to pay tribute to Ms Horton.

Florida governor Rick Scott tweeted: “Extremely saddened to hear about the loss of Darlene Horton in London. Ann and I are praying for her family and loved ones.”

Police and forensics officers are still at Mr Bulhan's house today, August 5.

Parmjit Singh, 36, a London-based DJ and events manager, has lived there for 30 years, and has known the Bulhan family for around seven years.

Pic: Mr Singh, SWNS

He said: “They genuinely are a nice family. They do keep themselves to themselves but they are a very nice family.

“They are a Muslim family, Somalian.

“It was just the mum with the three kids living there. One daughter, Sagal, around aged 23-24, Salah, aged 16, then Zakaria, aged 19.

“I see Zakaria as an innocent little kid. People on this street know him and his brother as the boys always playing football outside.

“He went to Graveney School and did GCSE’s and A Levels. It’s a really good school.

“I don’t think he was working or going on to further education but he may have been going to college.

“I’ve got a lot of good things to say about them. I carry a lot of DJ equipment and they were polite and would keep the door open for me when I came home.

“Sometimes they’d annoy me playing football, they’d keep ringing the buzzer to get back in.

“I still see them as the little boys playing football.

"But for the last two years it is as if Zakaria had gone undercover keeping himself to himself and stopped playing football.

"The only thing I could say about his mental health was that he may have been depressed or a bit upset.

"He didn't get to see his friends that much. They didn't have too much money.

"His mum and dad had separated, that could have been another key for being depressed".

Mr Singh described how his older sister, Sagal, was a rebel as a youngster but recently got heavily into Islam.

She would tell off her neighbours about drinking and smoking when she bumped into them on the stairs.

Mr Singh said: “Her mum caught her with a boy at the house and she used to smoke weed. When she was caught that’s when she changed.

“She would tell me I shouldn’t be smoking and that it’s bad for your body”.

He added: “It’s still unbelievable that this has happened. It’s a massive shock.

“I would love to hear that he’s got charged because I don’t think he’s physically capable of doing it.

"I don’t see him being able to stab someone. I’m in disbelief. I’m looking for someone to tell me it wasn’t him – he was just very quiet and very innocent.

“They had some domestics up there sometimes. I think the mum was quite strict.

“They weren’t fanatical Islamists, but they spoke about religion."

• Do you know Zakaria Bulhan? Contact the newsdesk on rebecca.taylor@newsquest.co.uk