The sheriff studied him from beneath leveled eyebrows. “You think she’s in some danger here?” he asked.
Mason didn’t answer the question. He turned to Helen Monteith. “Do you suppose,” he said, “you could help me check one phase of your alibi?”
“What do you mean, Mr. Mason?”
Mason said, “I want you to do something which is going to be a nerve strain. I hate to inflict it upon you, but it’s necessary. There’s one point we want to establish, immediately.”
“What?” she asked.
“I think I know the real reason for that original substitution of parrots,” Mason said. “I remarked a while ago that we’d probably never know just what caused Sabin to make that switch. Now I think we can get the real reason. If what I suspect is true, there’s an angle to this case so vitally important that... Do you think you could stand a drive to Santa Delbarra? Do you think you could point out to me the exact room in the hotel where you last saw your husband?”
“I could,” she said, “but I don’t understand why.”
Mason shifted his eyes to meet the steady inquiry in those of Sheriff Barnes. “We’ve been talking quite a bit about becoming hypnotized by circumstantial evidence. After a person once gets a fixed belief, he interprets everything which happens in the light of that belief. It’s a dangerous habit to get into, and I’m afraid I haven’t been entirely innocent, myself. I’ve been so busy pointing out the trap to others that I’ve walked into one myself without noticing what I was doing.”
Sheriff Barnes said, “I don’t know what you’re after, Mason, but we’ll rush things through. I have the matron coming over with all the personal property taken from Miss Monteith... Here she is now. Check this property and pay particular attention to the contents of your purse, Miss Monteith. Then, sign this receipt on the back of this manila envelope.”
Helen Monteith had just finished signing the receipt when Della Street entered the room and nodded to Mason. “All ready, Chief,” she said.