And now, driven into the corner which he had hoped to avoid, his retentive memory brought back a circumstance well-nigh forgotten. He addressed Barker, his voice soft-hopeless.
"You mean that Mrs. Lawrence was the woman in the taxicab?"
"Yes, sir." The "sir," which Barker used for the first time was respectful.
"Where had she been during the evening—after dark of the night of the—killing?"
"At home—I believe."
"You believe?"
"Yes, sir."
Carroll's eyes lighted. His voice cracked out accusingly: "Don't you know that that is incorrect?"
Barker shook his head. "Why, no, sir. Of course, I ain't sayin' positive that she was at home all evenin', but—"
"As I understand it," said Carroll slowly—"an accommodation train came in just about that time: isn't that a fact?"