There was the perplexing behaviour of Mrs.Oliver herself.

She had been troubled, greatly troubled, to find her window unbolted on two successive nights after she had taken care to bolt it.

Yet on the third night she actually unbolts it herself and leaving it unbolted puts out her light and goes to bed.

It seemed incredible that she should so utterly have forgotten her fears.

But still more bewildering even than her forgetfulness was the conduct of the intruder.
Upon that point he took Linforth into his counsels.
"I can't make head or tail of it," he cried.