Mrs Brown told BBC Scotland: "My father was every bit as much of a paedophile as Jimmy Savile ever was.
"My sad conclusion is that Moira is not the only child in the central belt of Scotland who suffered this fate. Whether we find her or not, we know we've looked. I hope to see results in the next few days."
She said it was her belief that there was a "paedophile ring" operating in the area at the time the schoolgirl went missing.
"Given recent events with Mr Savile, people are now realising that this is not a modern phenomenon. It has gone on for a long time," Mrs Brown said.