Isobel's _fiancé_, I foresaw a dreadful ordeal for both if Eric
Coverly was not in a position to establish an alibi.

I had been about to ask her if Coverly had been in her company on the
previous night when the interruption had occurred. Now if Gatton
should arrive and find me in Isobel's flat, what construction would he
put upon my presence?

Yet again I went to the window and peered anxiously up and down the
street. Every cab that approached I expected to contain the inspector,
and I heaved a sigh of relief as one after another passed the door.
Pedestrians who turned the distant corner I scrutinized closely and
was so employed when Isobel came running back to the room.

All her color had fled and her eyes were wide and fear-stricken.

"Oh, Jack, Jack!" she cried, "it is horrible, horrible! Eric is at his
solicitors' and they tell him that suspicion is bound to fall on
_him_! It's preposterous--unthinkable. It must have been some fiend
who committed such a crime, not a human being--"

"Then," I interrupted excitedly, "Coverly was not with you last
night?"

"No! That is the crowning tragedy of it all. He 'phoned me early in
the evening saying that he had an unavoidable business appointment to
keep. From the tone of his voice--"

She ceased speaking abruptly, and stared at me rather wildly.