Almost four months have passed since I first began to investigate the harrowing case of a beautiful little girl who appeared to have vanished into thin air, shortly after being tucked up in bed by her parents on holiday in Portugal.
Like a great many people in Britain, and millions more around the world, I have since become fascinated, almost to the point of obsession, with the Madeleine McCann mystery.
I have travelled repeatedly to the Algarve to interview potential witnesses and suspects; retraced the abductor’s possible escape routes and explored all manner of theories.
And I end most days by reading the strangely breezy and matter-of-fact web-log kept by Madeleine’s surgeon father, Gerry.
My curiosity has been heightened at least partly because those haunting last photographs of a beautiful, carefree child playing in the sunshine resemble so many treasured pictures in my own family album.
As a father of four, I can also identify with the dilemma that apparently confronted Gerry and Kate McCann on that fateful May evening in Praia da Luz. How do you enjoy an evening out with friends on holiday, and keep your toddler safe?
Yet something else has kept me utterly absorbed in Madeleine’s case, and it is certainly not the McCanns’ moth-to-a-flame courtship of the media (their latest interview, with Paris Match, is due to be published imminently).
Nor is it the initially well-meaning, but now ill-advisedly slick publicity campaign being masterminded by failed Liberal Democrat parliamentary candidate and party activist Justine McGuinness – a freelance PR who recently had to be dissuaded from arranging a photocall for Kate McCann at a Portuguese orphanage.
No, something far more disconcerting has kept me rapt with the Madeleine story. From the earliest days, a disturbing thought has nagged away at the back of my mind. Suppose her parents were somehow culpable?
Until yesterday, this was such a terrible notion as to be almost unspeakable, even within the confines of my own four walls, where my wife steadfastly refuses to countenance the possibility the McCanns could be anything other than the blameless, heartbroken parents they present themselves to be.