“Did Professor Arnell ever correspond with Dr. Crocker?” he asked.

“In the past quite a lot,” answered Baker. “Not since the quarrel, however. I remember he had a letter from Crocker saying that in view of his discourteous and unscholarly conduct he could consider their friendship at an end. He spoke of getting the letter framed, as a proof that he was one critic who did not spend half his time boosting his friends’ books, like so many of them seem to do.”

“I see.” Cunningham paused again. “Well, sir, does that exhaust your suspicions?”

“I think so,” said Baker slowly. “Unless I suspect Violet and myself, as I’m sure you must be doing inside that discreet mind of yours, Sergeant.”

Laughingly Cunningham disclaimed such unworthy suspicions, though he feared that his denial must sound strangely unconvincing to the other man. After all, Baker was the obvious person to be suspected. And he was a science master in a school, which meant that he would be able to get hold of some cyanide if he wanted it.

“Anyhow,” Baker added, as he accompanied the detective to the door, “you can be assured that I shan’t run away, Sergeant. I shall be on duty here until the end of term, which is—alas!—two or three weeks away yet. And I hope that you’ll have the guilty person under lock and key long before then, Sergeant, don’t you?”

“I hope so too, sir,” said Cunningham, but there was little conviction in his tone.

It was not until he was waiting on the platform of the railway station that Cunningham felt himself at leisure to consider what his information really amounted to, to sum up in a few sentences what he had learned, and to decide precisely how he would tell Shelley what he had discovered.

Baker had a complete alibi for the day. That was the first point. Moses Moss was the next suspect, and Dr. Crocker, to whom they had already had the attention drawn, would follow. The question of the will of Professor Arnell, Shelley already had under consideration, and no doubt they would have got hold of most of the other points without Baker’s assistance, willingly though it had been given.

Then Cunningham smacked his knee so hard and so resoundingly that an old lady sitting opposite him looked up in alarm.

“What a fool!” he said to himself. “Why on earth didn’t I think of that before?” He had forgotten to test Baker on the question of his last contact with the professor, the occasion when, if at all, he would have placed the poisoned sweet in the packet!

Chapter VI

Chapter VI

New Information