'I've never seen any sign of anything that suggest he has problems' - neighbours of man accused of going on stabbing rampage in London
Neighbours of a teenager being held over the Russell Square knife attack described him as a "quiet" and "pleasant" young man who enjoyed playing football with his younger brother.
The 19-year-old, Zakaria Bulhan, from Tooting in south London, is being questioned over Wednesday's rampage which left an American woman dead and five others injured.
Police have said the incident appears to have been triggered by mental health issues rather than being terror-related.
But shocked neighbours said they had seen no signs of anything being wrong.
Two police officers remained on duty outside the door of his family home on Friday, a council flat on the second storey of Robertson House, a small, six-flat building on a road adjacent to St George's Hospital.
One neighbour, who asked not to be named, said: "It is a bit of a shock. I am shocked and surprised that a neighbour could have done something like this.
"The mother is so pleasant and so kind, and I am shocked about him.
"He seems to be a very nice, pleasant person, like when I am going out or he is coming down the stairs he is very nice, saying 'Hi, how are you?'.
"I am also sorry for the mother because of what has happened now."
Bulhan is a Norwegian national of Somali origin who moved to the UK in 2002.
The man said he lives at the flat with his mother, who wears a full burqa, and his younger brother, who is about 12 or 13, but neither has been back since Wednesday.
He said he thought Bulhan also has a sister, but last saw her at the building around three years ago.
The neighbour said: "He is very quiet. Most of the time he goes out and plays football out the front in the playground with his brother and some friends, or in the garden at the back.
"They are a quiet family. The mother is very nice, very pleasant. When I go out shopping or out to work she is always a very pleasant person when passing in the stairs.
"She opens the door for my mother because she has a walking stick."
Speaking about the suggestion Bulhan may have mental health issues, the neighbour said: "That is what I was surprised about. He seems to be a normal person. I have never seen any sign of anything that would suggest that he has problems."
Other neighbours said people in the block kept to themselves and that they did not really see the family.
The flat was still being scoured by detectives on Friday, and police were expected to be there for much of the day.
Along with other items at the property, officers have been examining computer equipment, which was expected to be taken away later.
Officers from the murder squad carrying forensics bags were seen entering the property, and later two policemen wearing blue forensics overalls left the building.
Another neighbour, Parmjit Singh Bhamra, described Bulhan as a "quiet, academic boy who was a bit of a loner" who liked football, basketball and music.
Mr Bhamra, 36, a sound engineer who works for the BBC Asian network as DJ Precious and lives in the flat below, said: "It is shocking news. It is almost absurd because the young guy himself, Zac, is quite a little gentleman.
"He is quite polite, quite posh, quite academic - it is shocking to hear his involvement."
Mr Bhamra, who said he had known Bulhan for around seven years, described him as a "good boy" who was humble, helped his mother and would give him a hand carrying his sound equipment in and out of the building.
He said Bulhan, who is unemployed, lived at the flat with his younger brother Salah, who he thought was about 16, and his elder sister Segal, around 24 and known in English as Hannah, and their mother Safia, whom neighbours call "auntie".
Bulhan's father, a Somalian who Mr Bhamra thinks is from Norway, moved out after he split up with Safia, he said. Mr Bhamra added the family were "always polite", and called the two boys "innocent kids".
He said Bulhan was not a trouble-maker, but said he was "very impressionable" and could have been influenced by peer pressure from Somali friends in the area. The teenager went on to study at Graveney Secondary School in the sixth form, where Mr Bhamra himself had gone.
He said: "He would always tell me something good about school."
Another former classmate who went to Graveney School with Bulhan said: "I really didn't think he would do such a thing.
"Anyone you talk to from my year at Graveney will say you would never think he was capable of such madness."
A family friend said that Bulhan called an ambulance six months ago because he wanted to harm himself and had called paramedics on two other occasions recently for the same reason, The Times reported.
Police have said the suspect has a history of mental illness and that there was nothing to suggest he had been radicalised. But Mr Bhamra questioned the suggestion of mental illness, saying: "We have never heard of any type of mental illness, depression or that he had any mental conditions.
"I have lived here 30 years - I have never seen an ambulance here or him being rushed to hospital."