"In my business, you know, one acquires a very good ear for the truth." Grey laughed cheerfully and said: "I expect you do." "All the same, I'm glad to have it for certain," said Mr.Flexen, smiling at him.

"Well, I must be getting on; let me give you a lift as far as Loudwater." Grey thanked him and stepped into the car.
When he had set him down, Mr.Flexen drove on in frowning thought.
Colonel Grey was speaking the truth, and in that case neither James Hutchings nor the mysterious woman had committed the murder, unless they had deliberately returned for the purpose.

He did not believe that James Hutchings had returned; he thought it improbable that the mysterious woman had returned.
Even more important was the fact that this admission of Colonel Grey assured him that neither he nor Lady Loudwater had committed the murder.
Grey had evidently lied to shield her.

He had no less evidently learned that she did not need shielding.

That admission had not at all simplified the problem.
The next morning Scotland Yard telegraphed to him the reply to its cable to Captain Shepherd.