"Certainly. But the woman might have begun to sing immediately after Number One left."
"Before," insisted Laura. "The policeman listened while Number One was in the room. It was the song that made him stop. I am only going by what you told me. Your theory doesn't fit together."
Derrick frowned. "It is hard to put the pieces of the puzzle together, Miss Mason. Only in detective fiction does the heaven-born genius put this and that together in a flash. I--a mere mortal--am groping in the dark. I may discuss a hundred theories before I hit on the right solution. Nothing more can be done till I see Mr. Fane. As the woman was in his house, he must know----"
"He knows nothing," interrupted Laura imperiously; "he can't know. The man is ill at the seaside and----"
Derrick interrupted in his turn. "I'll wait till I hear what Mr. Fane has to say," he declared abruptly.
He rose to terminate the interview. As he opened the door Tracey entered hurriedly. "My car's found," he burst out.
"Where?" asked Derrick and Laura together.
"Stranded in the yard of Charing Cross Station."
Laura turned quickly on Derrick. "I beg you to observe, Mr. Inspector, that you cannot get to Westcliff-on-Sea from Charing Cross."
"I have not yet accused Mr. Fane," retorted the inspector.