"It's a startlin' notion," he observed at last. "There's never been a murder in Pen Mill yet--at least not in my time." "I don't say there has now," interrupted the doctor, with a slight touch of impatience. "It all depends upon whether any vessel went up the estuary last night in the fog." "We can find that out easy enough," chimed in the landlord. "Only a matter of enquiries at the lock. She couldn't 'ave got no farther--not till this mornin'." The Sergeant looked at him with a certain severity. "I know my business, thank ye, Mr. Robinson. When I want any help I'll ask you for it." He turned to me. "What's your opinion, sir? Any party in your knowledge as had a grudge against the deceased?" I shook my head. "I am absolutely ignorant about his private affairs," I answered. "As I told you before, he was one of the most reserved men who ever lived. For all I know he might have been at daggers drawn with the entire neighbourhood." "Was he violent tempered or quarrelsome?" asked the doctor. "I never saw any sign of it," I replied. "We were alone together for a month, and I couldn't have wished for a better servant." "I reckon our first idea was the right one," announced the Sergeant. "It must have been some craft coming up in the fog that did it. The odds are they thought it was an empty boat they had run down, and, seeing as they'd be liable for damages, they made up their minds to say nothing about it." He took out his note-book and sucked the stump of a pencil. "What time was it when the deceased left the island?" he enquired. "I couldn't say exactly," I replied. "It was probably between five and six." "Just about high tide," he observed, in a satisfied voice. "That more or less settles it to my way of thinking." He asked me one or two other questions, to all of which he noted down the answers; then, with the air of a man who has efficiently discharged a difficult duty, he snapped together his book and replaced it in his pocket. "I don't think we need detain you any longer, Mr. Dryden. If the Head Constable comes over he'll probably wish to speak to you, but as like as not he'll leave the case to me. I'm going along to the lock straight away now, and it's my belief that before to-night we'll have our hands on the party that's wanted." "I shouldn't be surprised, Sergeant," I said untruthfully. "All the same, it will be a smart bit of work if you do." The doctor, who appeared to have lost interest in our conversation, picked up a piece of sacking and spread it across Bascomb's body. I had an idea that he was very far from satisfied, and the moment we left the coach-house my suspicions were confirmed. Drawing me slightly to one side, he glanced impatiently at the Sergeant, who was engaged in giving some instructions to his subordinate. "The man's a fool," he said in a low voice, "but there's nothing more to be done at present. We must wait until the Head Constable comes over."