Attempts by MPs to solve the mystery of the missing child abuse files presented to ministers in the 1980s appeared to hit a brick wall when the top home office official gave evidence to a Commons committee investigating the affair.
Permanent secretary at the department, Mark Sedwill, said he did not know who had authorised destruction or removal of 114 files related to claims of a paedophile ring in Westminster in the 1980s.
He said there were flaws in the system and he was concerned that the missing files had probably been destroyed or removed.
He also repeated his previous remarks that an independent investigation he had commissioned last year into the procedures found no evidence anything inappropriate had been done.
However, he agreed that a log of the titles of the missing files could be made available to the committee and he said the 2013 review, which not even the home secretary Theresa May has seen, might be published with names and addresses struck out.
He also urged anyone, including government whips, who had any information relevant to the investigations to provide it. That raised the prospect of the whips being quizzed by the inquiries over what they knew about allegations concerning named politicians and which they may have kept secret.
The MPs were clearly frustrated at what now looks like the impossibility of ever getting to the bottom of what happened to the 114 files or what was in them.
And, while they were largely impressed by Sedwill's transparency and willingness to answer direct questions, chairman Keith Vaz said the 2013 review had not been satisfactory.
Other MPs, including one of the original campaigners Simon Danczuk, later said it was highly troubling that Sedwill had simply relied on the judgement of the inspector he appointed to carry out last year's review.
The focus will now move to the over-arching inquiry launched by the home secretary which, it has been announced, will be headed by retired senior judge Elizabeth Butler-Sloss.
She is highly regarded in Westminster, partly for her handling of the Cleveland child abuse inquiry in the 1980s and the inquest into Princess Diana.
But the size of her task is becoming clear with growing concern that the inquiry may well last for many years, meaning victims will have to wait even longer for justice.