Murdered girl was 'at risk'
The bodies of Ukleigha Batten-Froggatt and 34-year-old Nicole Batten were found after police broke into their flat in Somers Town.
Ukleigha had been strangled and her mother stabbed in the chest.
Today it emerged that the girl had been under the watch of social workers amid concern that she was being neglected because of her mother's heavy drinking.
Neighbours had reported violent rows between Miss Batten and her boyfriend, a suspected drug addict, who had moved into the flat three weeks earlier.
There were also reports that the mother may have been taking crack cocaine.
The deaths raise echoes of the shocking case of Victoria Climbie, the eight-year-old who died at the hands of her aunt and the aunt's boyfriend in February 2000. A report found that childcare professionals at Haringey council had missed eight opportunities to save her life and had closed the file on her a week before she died.
In another case, Toni-Ann Byfield, seven, was under the care of social services when she was shot dead with her drug-dealer father on the doorstep of his Kensal Green bedsit.
Camden Social services confirmed today that Ukleigha had been on a multi-agency child protection register.
The council has launched a "combined review" with police into the circumstances surrounding her death. A spokesman said: "We will look at all the support and intervention given to the family by the agencies. We cannot comment further while there is a police investigation."
Miss Batten's partner Mark Nicholas is being questioned today in connection with the double murder.
He was arrested at a bed and breakfast in Hackney last night after police issued his name and photograph in connection with the killing.
Detectives were called to the address in Hackney just before seven last night after a member of the public recognised the picture.
Nicholas, who is believed to be from Pembrokeshire, was being interviewed at a police station in east London. The bodies of Ukleigha and her mother were found at their flat in Ossulston Street last Thursday. They may have been in the flat for several days.
Initially, police believed that her mother had smothered her before stabbing herself. However, a paediatrician and pathologist later concluded they had both been murdered.
Police had been alerted by social services on Thursday after the six-year-old failed to turn up at school that Monday.
Ukleigha was last seen the previous Friday when she had been picked up from school by her mother at 6pm.
Experts believe the couple were murdered "two or three" days
before, or perhaps even earlier because of the cold weather. Today, a single bunch of flowers had been left at the entrance.
A neighbour said: " Little Ukleigha was a bubbly little thing. She was always polite and well looked after. They were really close, really lovely."
The case of Victoria Climbie was one of the most shocking of recent years. She was brought to Britain by her great-aunt Marie-Therese Kouao in 1999.
Kouao and her boyfriend, Carl Manning, were jailed for life for murder and child cruelty. In another case, Alexandra King was on the child protection register and aged just two and a half months when she died in agony from blood poisoning caused by severe nappy rash.
She had been seen by social workers 28 times in the weeks leading up to her death but was allowed to remain with her heroin addict mother, Maryann Pickering, 27, of Lanarkshire, who was jailed this week for 12 months.
Another notorious case involved social workers in Dumfries who admitted they knew eleven-weekold Caleb Ness was being abused by his brain-damaged father and drug addict mother. Despite being placed on an at-risk register days after his birth, Alexander Ness shook him to death in 2001 while his mother was out.