I notice that Kate McCann distinguishes between 'nutty' and 'nasty' letters; the 'nutty' ones are described as 'nonsensical'. She doesn't elaborate much on what this nonsense consists of, but she does mention facts, figures and symbols;
Within days of Madeleine’s disappearance, several people with major psychiatric problems made their way over to Praia da Luz and somehow managed to get to see Gerry and me. In spite of the state we were in, we found it hard to ignore anybody who was trying to help, even if what they were telling us was complete nonsense. Some of them were very persistent: they would track us down again and again, wielding their piles of papers full of totally
illogical ‘facts’, figures and symbols. It was draining and at times a little scary. [madeleine]
I wonder how the press, desperate for stories, missed this parade of seriously disturbed people beating a path to the McCann's door?