An independent inquiry into the abuse and murder of eight-year-old Victoria (Anna) Climbie has had to hire a team of private investigators to track down witnesses.

Some people who have been asked for witness statements have refused to respond letters from Lord Laming's inquiry team while others have moved to Australia and New Zealand.

The inquiry needs to find some 30 people in time for public hearings into the case in September. Most have now been traced but the whereabouts of about five are still being tracked down. They include people who had worked "at agencies involved in the case".

Lord Laming has said that he will legally force people to produce witness statements if he has to.

So far, the inquiry team has collected 1,500 documents, running to more than 12,000 pages. The hearing begins on September 26 at the Elephant and Castle building in London.

Victoria died at the hands of her aunt, Marie Therese Kouao and Kouao's boyfriend Carl Manning, in 1998 after months of abuse and neglect. She had 128 injuries on her body and had been beaten with buckles and bicycle chains and been forced to sleep tied up in a binliner in a freezing bathroom.

Kouao, 44, and Manning, 28, both of Tottenham, north London, were jailed for life in January after being convicted of the youngster's murder.

Kouao and Manning have been given extra time to send in their own witness statements on their version of events. No decision has yet been taken on whether or not they will be invited to give evidence in person.

Victoria's case was one of Britain's worst cases of child abuse and the youngster died despite being known to social services, police and hospitals who were accused of "blinding incompetence" during the trial.