"There are three, I believe." Von Blon spoke easily. "There's one in Mrs. Greene's room, one in Sibella's room, and, I think, one in the kitchen. The main phone is, of course, in the lower front hall."
"A regular central office," growled Heath. "Almost anybody coulda listened in." Suddenly he fell on his knees beside the body and unflexed the fingers of the right hand.
"I'm afraid you won't find that cryptic drawing, Sergeant," murmured Vance. "If the murderer shot Rex in order to seal his mouth the paper will surely be gone. Any one overhearing the phone calls, d' ye see, would have learned of the envelope he was to fetch along."
"I guess you're right, sir. But I'm going to have a look."
He felt under the body and then systematically went through the dead man's pockets. But he found nothing even resembling the blue envelope mentioned by Ada. At last he rose to his feet.
"It's gone, all right."
Then another idea occurred to him. Going hurriedly into the hall, he called down the stairs to Sproot. When the butler appeared Heath swung on him savagely.
"Where's the private mail-box?"
"I don't know that I exactly understand you." Sproot's answer was placid and unruffled. "There is a mail-box just outside the front door. Do you refer to that, sir?"
"No! You know damn well I don't. I want to know where the private—get me?—private mail-box is, in the house."
