The Metropolitan Police confirmed today that the family of a teenager stabbed to death in a South London tower block yesterday had made an allegation of assault against a man who had been harassing her.

The body of Arsema Dawit, who turned 15 on Friday, was discovered in the lift at the block near Waterloo station yesterday afternoon. She had been stabbed ten times in an attack so frenzied that the blade of the knife was left embedded in her body.

A friend, Simon Tesfaghiorgish, said today that Arsema had been harassed by an older man who stalked her and threatened to kill her. Her family had complained to police.

Mr Tesfaghiorgish told reporters: "I didn’t know him but he had been harassing her. The mother told the police a number of times. The police said they couldn’t take any action. What they want is, after things happen, they want to know."

He said that the family were going to complain about the police handling of the situation. "We are going to complain about this. He beat her and threatened to kill her."

In a statement, Scotland Yard said: "It has been established that Arsema and the suspect knew each other but the exact nature of their relationship is unclear at this stage.

"Police did receive an allegation of assault made by Arsema and her family in April this year, an ongoing investigation was set up and contact was made with the victim with a view to further progressing that investigation."

Detective Chief Inspector Caroline Goode of the Homicide and Serious Crime Command said: "At this stage I am trying to establish the true nature of the relationship between Arsema and the man in custody. We are speaking to her family and friends to help build a picture of events leading up to the murder and to help piece together the relationship between them."

Arsema’s body - still clothed in her school uniform - was found slumped in a lift in Matheson Lang Gardens at around 4.30pm yesterday.

A man in his 30s, who was arrested last night, was being questioned about the murder at a south London police station today.

Wayne Fort, a neighbour whose partner and nine-year-old daughter found the body, said Arsema had been troubled in the past by a man.

"I encountered an incident about two months ago," he said, referring to an argument between the man and a female member of Arsema’s family in the stairway of the flats. He said the girl was warning the man not to harm her sister again.

"There was a chap who seemed to be infatuated with her," he said. "He seemed to have met her at the church. I could see from the efforts of the elders of the family they were trying to get rid of the man."

Mr Fort said his daughter was extremely upset after finding the body. "She is in a very bad state - she didn’t sleep much last night," he said.

The murdered teenager had celebrated her 15th birthday with her family on Saturday, although police said her actual birthday was on Friday.

A woman believed to be Arsema’s mother was taken away from the flat in a police car today.

Berekati Asfeday, a family friend, said: "Her mother can’t talk, just cry, cry, cry, non-stop cry. She was in the church with me, she was a singer. She was a beautiful girl, just a beautiful girl."

Mrs Asfeday said the teenager was a devoted churchgoer, attending St Michael’s Orthodox Church in Camberwell every Saturday and Sunday. A neighbour said she heard an argument raging in the staircase of the flats in the minutes before the teenager is thought to have been stabbed.

Cosima Paniza, who has lived in the block for 28 years, said she heard shouting sometime before 4pm yesterday. "I went to put my rubbish in the chute and I heard the man and the girl arguing," she said. "I couldn’t get the words of the girl because she was shouting so loud. It sounded like he was threatening her."

Mrs Paniza said she returned to her flat and later found out the girl had been murdered.

Cathy Loxton, the principal at Arsema’s school, the Harris Academy in Bermondsey, described her as a popular pupil. She said: "Arsema was a popular, friendly and well-behaved girl who had much to contribute to our school community."

Arsema’s schoolmates were told of the teenager’s murder during special assemblies today. A spokeswoman for the school said many youngsters were extremely upset and some had been sent home.

She said: "This is being broken to them in year groups. It is very sad. It is very hard at the moment."

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