Heck and Wilde had studied the map with a magnifying glass for an hour before they decided on this route. It seemed perfect for Heck’s purposes, an obscure rocky way that went nowhere except to what looked like a hopeful observation point above the village of Schwarzenkirche. A place where he just might have an eagle’s eye view of the Boden house and anyone who came to it or left. A place where no one was likely to go when on their daily business of herding goats or heading for the high meadows to scythe the grass and oats.

Colonel Appache had been summoned to Flint Kaserne at Bad Tölz by Patton, so Heck had gone straight to the Garmisch quartermaster for equipment: a small radio transmitter, mountain camouflage, sleeping bag, binoculars, weapons and C-rations. A driver had dropped him two and a half miles from the village, and he had hiked from the valley along difficult rocky terrain, through forest land, well away from the routes the villagers were likely to take.

It wasn’t a long hike, but he was taking it slow because he had to be sure he wasn’t observed. Every ten minutes he stopped and spied out the lie of the land.

All was clear. From above and below he could hear the comforting clanging of cow bells in the high meadows and the occasional bleating of sheep. The dominant colours were the dark green of the needle-laden fir trees, the lush green of the grass, the grey of the rock faces and the blue of the sky.

According to the map, he was at an altitude of just over 1,600 metres when he came to a platform of rock. This was the spot they had decided would be the perfect observation post, but he was in woodland and at first he thought he would have no view.

He moved on a little further, across a narrow escarpment and came to an even better rock platform. It was about eight feet in width and went back about twenty feet into the cliff face. Above him there was nothing but an overhang and then a sheer ascent, below him, woods on a steep slope. But this time he had a clear view over the top of the trees.

He had found what he wanted – a panorama of the village about four hundred feet below. No one would see him from down there unless they were specifically looking for him, and no one could approach him unless they came along the path marked on Jaeger’s map.

Removing the radio pack and the rest of his equipment, he stretched out on his back, looking up into the sky and the towering peaks. A pair of alpine choughs caught his eye and he watched them dance and play in the air.