Sally lit her cigarette, inhaled deeply, and expelled the smoke down her nostrils. "Quite a good point. But I'm nearly as much in the dark as you are. Not entirely, because I have the advantage of knowing my sister and her husband pretty well. Do let's be honest! It must be evident to a child that things look rather black against my brother-in-law. He apparently had a motive for killing Ernest Fletcher; his sudden return from Berlin was unexpected and suspicious, and now you seem to have collected proof that the alibi he gave you for 17 June was false. My advice to my sister is to keep her mouth shut. If her solicitor were here I fancy he would echo me. Because, Mr. Superintendent Hannasyde, you are trying to put over one big bluff. If you'd any real evidence against my brother-in-law you wouldn't be wasting your time talking to my sister now."
"Very acute of you, Miss Drew; but aren't you leaving one thing out of account?"
"I don't think so. What is it?"
"You are preoccupied with the idea of Mr. North's possible guilt. It is quite natural that you should not consider the extremely equivocal position of your sister."
She gave a scornful laugh. "You don't think she had anything to do with it!"
"Perhaps I don't. But I may think that she knows much more than she has told me. You wish me to be frank, so I will tell you that Mrs. North's evidence does not tally with those facts which I know to be true."
Helen came forward, throwing up a hand to silence her sister. "Yes, you told me that the last time you were here. I agree with what Miss Drew says; it is time to be frank, Superintendent. You believe that the man I saw was my husband, and that I recognised him. Is not that so?"
"Let us say, Mrs. North, that I consider it a possibility."
"And I tell you that it is not so!"
"That is what I propose to find out," said Hannasyde. "You yourself have given me two separate accounts of your movements on the night of the 17th. The first was before your husband arrived here on the morning after the murder; the second, which was apparently designed to convince me, first, that the mysterious man seen by you was shown off the premises by Fletcher himself; and, second, that Fletcher was alive at 10.00 p.m., you told me after the arrival of your husband. You will admit that this gives me food for very serious thought. Added to this, I have discovered that Mr. North left his flat at 9.00 p.m. on the evening of the 17th, and only returned to it at 11.45."