Detectives are questioning a man in his 30s after a schoolgirl was stabbed to death in a block of flats.

A neighbour returning home with her young daughter stumbled across the murdered 15-year-old girl in a lift just before 4pm on Monday.

The victim was wearing her school uniform and had a knife handle sticking out of her body, local residents said.

Paramedics rushed to Matheson Lang House in Baylis Road, near London's Waterloo Station, but could not revive her and she was pronounced dead at the scene.

Shortly afterwards a man in his 30s was arrested in the Lambeth area of London and held for questioning, Scotland Yard said.

Police are keeping an open mind about motive but do not believe the killing was gang-related.

Neighbours said they believed the girl was Somalian and a pupil at the Harris Academy in Bermondsey, south-east London.

She is the 16th teenager to fall victim to violent crime in the capital so far this year.

Local resident Sharon Moore said the girl and her family had lived in Baylis Road for about 12 months.

She added: "You think you are fine once you are in the building, this is the last thing you expect.

"I'm extremely shocked because once I'm in the door and I get in, I think I am safe."

Nana Lumaya, 32, whose sister lives on the fourth floor of the block of flats, said: "My sister's husband came in and one guy was calling an ambulance on the phone.

"They told him not to go in because there was something wrong in the lift. She was bleeding and everything."

It is believed the girl, who was wearing a pink and blue school uniform when she died, lived on the fourth floor of the building.

Hermance Deh, who lives opposite the flats where the murder happened, said she refused to let her children out after school because of safety fears and was planning to apply to the council to move house.

She said: "I'm scared for my children. I'm shocked because it's a young girl. My children don't go out after school, they don't hang around here."

One neighbour who described himself as a friend of the girl did not want to comment but said she would be in his prayers.

Recently-elected London Mayor Boris Johnson has pledged to make combating knife crime one of his top priorities.

His spokeswoman said: "The Mayor is aware of the latest reports and is extremely troubled by them.

"It would not be wise to comment in detail until the full facts have been established, but his thoughts are with the family of this murdered child.

"The stabbing reinforces the need to make tackling violent teenage crime the top priority for London."

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