Cardman started with surprise at the emotion in Monk's voice. "There was no reason," he said gravely. "That is why Miss Mary believed he had been murdered. More and more she became convinced that either he had found something in the tunneling works or he was about to, and for that he had been killed."

"What made her more convinced?" Monk said quickly. "Did something happen, or was it simply her need to clear her father of suicide?"

"If I knew, sir, I'd tell you," Cardman replied, looking directly into Monk's eyes. There was a kind of desperation in him, as if he was clinging to a last thread of hope too delicate to name. "Miss Mary read all through her father's papers, sat all day and up half the night. Over and over she searched them. Many's the time I'd go to his study and find her there at his desk, or fallen asleep in the big chair, one of his books open in her hands."

"What kind of book?" Monk did not know what he was looking for, but Cardman's emotion caught him also.

"Engineering," Cardman said, as if Monk should have understood.

Monk was puzzled. "Engineering, did you say?"

"Mr. Havilland was a senior engineer and surveyor for Mr. Argyll's company, until the day of his death. That's why they quarrelled. Mr. Argyll's company has never had a bad accident-in fact, they're better than most for safety-but Mr. Havilland believed it would happen."

"And he told Mr. Argyll?"

Cardman shifted position slightly.

"Yes, of course. But Mr. Argyll said it was just his feelings about being underground, closed in, as it were. Mr. Havilland was embarrassed to admit to them. Argyll as much as called him a coward, albeit politely. Of course he never used that word."

"Was that what Miss Havilland was doing also, enquiring into engineering, as regards the tunnels?"

"Yes, sir. I'm certain of it."

"But she found nothing, either?"

Cardman looked chagrined. "No, sir, not so far as I am aware."

"Did she continue to see Mr. Toby Argyll?"

"She broke off their agreement, but of course she still saw him socially now and then. She could hardly help it, since he was Miss Jennifer's brother-in-law, and the Argyll brothers were very close."

"Do you know Mrs. Argyll's feelings on the subject?" Monk asked. "She was surely caught in the middle of a most unfortunate development."

Cardman's lips pressed together before he spoke.

"She was loyal to her husband, sir. She was convinced that her father's fears had unbalanced his judgment, and she was annoyed with Miss Mary for pandering to him rather than encouraging him to abandon the matter." There was a wealth of anger and distress in his voice.

Monk was bitterly aware that the house in which Cardman lived was the center of a double disgrace, and there seemed no one left to care except the butler and the other servants for whom he was responsible.