“Well, you stay here till the doctor comes. I’ll go and have a chat with Houlder. Just throw your light over the floor for a minute. Hullo, what’s this?”

He strode across the cellar and carefully picked up a small automatic. “Hasn’t been fired,” he muttered. “Now I wonder who that belongs to? Just see if you can spot anything else. Don’t touch it, if you do.”

He went upstairs again, and drew Mr. Houlder aside into a quiet corner. Mr. Houlder’s story was a very simple one. His foreman had orders to leave the key to the house with Mr. Briggs, the confectioner, three doors off. Mr. Briggs was Houlder’s brother-in-law. The reason for this arrangement was that whoever came on the scene first could get the key and start work. On Saturday the key had been left as usual, about 12.30.

On Saturday evening, about nine o’clock, Mr. Briggs had come to his place and told him that Mr. Lacey, who knew about the key arrangement, had rung him up to say that a Mr. Martin was coming to inspect the drains. Mr. Lacey was to have met him at two o’clock, but would be delayed. Would Mr. Briggs keep a lookout for him and give him the keys. Mr. Briggs had promised to do so, and his daughter Marjorie had seen Mr. Martin, who had promised to bring back the keys, but had not done so. Mr. Briggs had forgotten all about them until the evening, and then, finding that the door of Number 407 was securely locked, had supposed that Mr. Martin had gone away with the keys in his pocket. Mr. Houlder had agreed with this theory, and had given Mr. Briggs a duplicate key which he happened to have.

The foreman had called on Mr. Briggs, and had been given the duplicate key. But when he came to try the door, it would not open. He made several attempts but, finding them unavailing, desisted and made his way through a window at the back. He then discovered that the door was bolted on the inside, a circumstance which puzzled him tremendously. Shortly afterwards the electrician arrived, and his thoughts were diverted into other channels.

Inspector Whyland spent a few minutes talking to the foreman, who confirmed the latter part of Houlder’s story, and had barely finished his enquiries when the doctor arrived. The two went down to the cellar together, and the doctor, without wasting words, proceeded to examine the body, Whyland watching him intently.

“Poisoned!” pronounced the doctor, after a short interval. “Prussic acid, by all signs of it, but I can’t be sure till I’ve made a post-mortem. You’ll have him taken to the mortuary, of course? Queer place to choose for suicide. How did he get in here?”

Inspector Whyland shook his head. “I don’t think it’s a case of suicide, doctor. Look here!”

He pointed to the numbered counter. The doctor glanced at it and sniffed contemptuously. “You fellows have got counters on the brain since that business last month,” he said. “How do you know he didn’t put it there himself to throw you off the scent? It’s not uncommon for suicides to try and make their deaths look like murder. You’ll find there’s some question of insurance behind it. Well, I’ll be along at the mortuary and let you know the result of the p.m.”

The doctor bustled away, and Whyland, having made arrangements for the removal of the body, made a very careful examination of the cellar. This done, he sent the constable for the electrician, and asked him to look round and see if he could find anything which had not been there when he left on Saturday.