Theresa May says she was informed a whistleblower that claimed to know about alleged funding of a paedophile campaign group had chosen not to be interviewed by the Home Office.
Tim Hulbert had told ITV News he was not interviewed during a Home Office probe into claims the department had provided money to the Paedophile Information Exchange.
Ms May told the Home Affairs Select Committee "the information I have got is that he was invited for an interview and then decided not to undertake that", having instead given information to the Metropolitan Police that "could be shared" with the department's investigation.
The Baroness says she did not consider the "difficulties" caused by her background and family connections to the child sex abuse inquiry.
Questions have been raised of former High Court judge Baroness Butler-Sloss since her appointment last week.
22 police officers are now assigned to Operation Fernbridge - the probe into claims of a Westminster cover-up of sex child abuse.