An inquiry begins today into how Soham killer Ian Huntley got a job as a school caretaker despite being a suspected sex offender.
The investigation was ordered by British Home Secretary Mr David Blunkett after revelations about Huntley's past, involving allegations of underage sex and rape.
Huntley (29) murdered Jessica Chapman and Holly Wells in August 2002 in the house that came with his job at Soham Village College in Cambridgeshire and was on the same site as the 10-year olds' primary school.
He was sentenced to two life terms by an Old Bailey judge last month.
Checks by police in Cambridgeshire and Humberside - where Huntley came from - failed to reveal the full extent of the allegations that built up against him as he alternated between using his mother's maiden name of Nixon and his own.
The chairman of the inquiry, former senior civil servant Sir Michael Bichard, declared last week the case raised issues of public interest.
Members of both Humberside and Cambridgeshire police are likely to appear along with social workers and other officials.
Humberside's Chief Constable Mr David Westwood has already apologised for some of the mistakes, saying an investigation had revealed "some system failings and elements of human error".
His force had had 10 contacts with Huntley over a four-year period, including eight sexual allegations.
North East Lincolnshire council said it had investigated five allegations against Huntley - four of underage sex and one of indecent assault. It had not alerted Cambridgeshire council or the police because he was never prosecuted.