we got rid of this nurse that's here now, and put in one of our own women from Headquarters?"
Von Blon looked up with eager approval.
"An excellent plan!" he exclaimed.
"Very well, Sergeant," agreed Markham. "You attend to it."
"Your woman can begin to-night," Von Blon told Heath. "I'll meet you here whenever you say, and give her instructions. There's nothing very technical for her to do."
Heath made a notation in a battered note-book.
"I'll meet you here, say, at six o'clock. How's that?"
"That will suit me perfectly." Von Blon rose. "And now, if I can be of no more service . . ."
"That's quite all right, doctor," said Markham. "Go right ahead."
But instead of immediately leaving the house Von Blon went up-stairs, and we heard him knock on Sibella's door. A few minutes later he came down again and passed on to the front door without a glance in our direction.
In the meantime Snitkin had come in and informed the Sergeant that Captain Jerym was leaving Police Headquarters at once and would arrive within half an hour. He had then gone outside to make his measurements of the footprints on the balcony steps.
"And now," suggested Markham, "I think we might see Mrs. Greene. It's possible she heard something. . . ."
Vance roused himself from apparent lethargy.
"By all means. But first let us get a few facts in hand. I long to hear where the nurse was dur-
