What, then? An ugly precedent springs to mind. Yossele! I exclaim. Yossele Schumacher was an Israeli child who was kidnapped in 1960 from his Sabbath-breaking parents by a heart-broken grandfather and a rabbi’s wife, Ruth Blau, intent on raising him in their stringently religious way. He was hidden for two years in ghetto homes in Bnei Berak, Brooklyn and goodness knows where else until common sense and threats of prosecution persuaded the zealot kidnappers to release him, on assurances that he would continue to receive a religious education.

For months on end, while Interpol searched in vain and the state of Israel squirmed with embarrassment, yeshiva students in Jerusalem danced on the streets, taunting police with cries of ‘Where is Yossele?’ sung to a Purim festival tune. Set against the might of a modern state and international law, the medieval walls of rabbinic orthodoxy had managed to hide a wanted child for as long as they liked – until they were good and ready to give him up on favourable terms.

It does not take a great leap of memory to recall that Dovidl, too, had been successfully concealed and transported by Hassidim during a British police search. Have they done it again? Is it conceivable that he got the yeshiva community to conspire in a second disappearance, persuading them that he was being harassed by a pursuer from his former life – me? Or has he simply done a runner all on his own, telling no one, not even his wife?

Easily done: drive the van to the top of the bank, with no risk of being seen so early. Change clothes, shave beard. Step outside. Wedge accelerator down with a piece of wood. Take off brakes. Stand well back. Then walk a short mile to the station and catch a bus or train to anywhere. A Labour Cabinet minister, John Stonehouse, dumped his clothes on a deserted beach, disappeared, and turned up years later in Miami. Lord Lucan, a gambling aristocrat, murdered a nanny and fled his Belgravia home, never to be seen again. Every week, some innocuous farm-worker or bank clerk walks out on wife and family without further trace. It does not require exceptional brilliance or vast wealth to vanish and stay hidden. A genius like Dovidl could do it twice, unaided.

So, what next? Wait for clues. The nine-seventeen sighs deeply and starts pulling out of Tawburn station. It crosses the river within seconds, overlooking the accident scene. A dripping blue camper-van is being hauled by crane from the water. It’s Dovidl’s, all right. No mistake.