It proved, however, that our vigil was not to be so long as Holmes had led us to fear, and it ended in a very sudden and exceptional fashion. In an instant, without the least sound to warn us of his coming, the garden gate swung open, and a lithe, dark figure, as swift and active as an ape, rushed up the garden path. We saw it whisk past the light thrown from over the door and disappear against the black shadow of the house.

There was a long pause, during which we held our breath, and then a very gentle creaking sound came to our ears. The window was being opened. The noise ceased, and again there was a long silence. The fellow was making his way into the house. We saw the sudden flash of a dark lantern inside the room. What he sought was evidently not there, for again we saw the flash through another blind, and then through another.

'Let us get to the open window. We will nab him as he climbs out.' Lestrade whispered.

But before we could move, the man had emerged again. As he came out into the glimmering patch of light, we saw that he carried something white under his arm. He looked stealthily all round him. The silence of the street reassured him. Turning his back upon us he laid down his burden, and the next instant there was the sound of a sharp tap, followed by a clatter and rattle. The man was so intent upon what he was doing that he never heard our steps as we crept across the grass.