"We will try one of those French windows," he whispered after returning to my side.

The house was a two-story cottage with a verandah opening on the south side facing a lawn. On to this verandah windows opened from both the dining and sitting-rooms, the servants' quarters being on the other side of the house.

We went round the angle of the building and tried the first window. It was fastened. With cat-like tread Forrest glided on to the second. It was one of the two giving entrance to the sitting-room. A sibilant sound from the detective's lips took me to his side. Without hesitating a second, he threw back the casement and stepped into the darkness.

"Come," he muttered, and I followed.

Heavy curtains veiled the windows and past these the darkness was thick enough to be felt. Of a sudden there was a crack which made me start. It was only Forrest striking a match. With imperturbable confidence, he stepped towards a table and lit the lamp which stood thereon. I felt exceedingly uncomfortable, but Forrest obviously knew no such qualms, for he at once proceeded to examine every object in the room. So far as I could see, there was nothing at all unusual about the place. The room was in exactly the same condition as I had observed it hundreds of times before when I had dropped in for a smoke and a chat. On the table, beside the lamp, was a tantalus and a glass, and a half empty syphon. The glass had been used and the ash on the floor, beside an armchair, showed that a cigar had accompanied the drink. A pair of slippers lay on the hearth rug as if they had been carelessly kicked off. Forrest pointed to them.

"Mannering is not at home," he said. "If he had gone to bed, these would not be here."

"I hope he will not return while we are about," I muttered.

"It would be a little awkward for him," said Forrest, calmly. "I should be compelled to arrest him in self-defence, and I am not prepared to do so at present."

He did not, however, hurry his movements in any way as he proceeded to deliberately search the room. Only once did he pause, and that was when he discovered a continental time-table of recent date. He brought the book to the light and turned over the pages carefully. A gleam of exultation crossed his face, as he pointed out to me a trace of tobacco ash between the pages which gave details of the train service between Vienna and Amsterdam.

"We are on the right track," he observed.

But that one slight piece of evidence was all that the most careful examination of the room revealed, although there was not a drawer nor a shelf which he did not overhaul.

"We must try his bedroom," he remarked, when he had finished with the sitting-room.

"What about the servants?" I asked.

"If they are not asleep, they will merely imagine that it is their master going to bed," he replied, as taking a candlestick, which stood on an occasional table near the door, he passed out of the room. I followed him upstairs, with my heart in my mouth, and pointed out to him the door of the room which Mannering occupied. As Forrest turned the handle and entered, I was quite prepared to make a bolt for it. I should not have been a bit surprised to have discovered our suspect sleeping quietly within. But Forrest turned and beckoned me to enter. The room was empty, and this time I assisted the detective in his search. Between us we subjected the bedroom and the adjoining dressing-room to the closest scrutiny, but without result. We could not, unfortunately, make an exhaustive examination, for there were one or two ancient presses which were locked, and the Chubb safe let into the wall by the bed head was likewise fastened.

The detective shrugged his shoulders when we had done.

"As we haven't a burglar's outfit, we shall have to wait until we have a search warrant," he muttered.

With a disappointed air he led the way out of the room. On the landing he paused. His keen gaze had rested for a moment on a travelling bag which stood under a table. There were the remains of a number of labels upon it and he scanned them carefully. There was no sufficient of any one of them left for identification.

"He's a clever devil," he whispered.

Then he opened the bag and again his countenance lightened. Inside was an empty bottle bearing the label of a London chemist, with the additional superscription—"Peroxide of Hydrogen."

"The fair hair is accounted for," commented Forrest. "And as for the dye which would restore his locks to their natural colour, I presume he has it under lock and key."

He slipped the bottle into his pocket and returned downstairs, I following at his heels.

"There's not enough at present against him to warrant his arrest," he said, when we were again in the sitting-room.

"Then why not have a look round his workshops," I suggested.

"His what?" queried Forrest, eagerly.

"Haven't I ever mentioned them to you? Haven't you ever heard that Mannering spends all his spare time in experimental motor construction?" I asked in surprise.

"I think I have heard it mentioned, but until this moment I have always thought it was chaff," he replied.

"Good heavens!" I ejaculated.

"I should have been inside that shop a couple of months ago," he continued, "if I had thought—— Whereabouts is the shop?"

"Just at the back of the house and abutting on the side of the road," I explained. "The old coach-house and stables." Then as the thought occurred to me, I continued, "Why I heard him tell you of his work himself."

"That's precisely the reason why I paid no attention to it," said my companion. "Can you take me to the place?"

I led the way through the French window, Forrest putting out the light before he followed me, and carefully closing the casement behind him as he stepped on to the verandah. A clock, somewhere in St. Albans, struck the half after two as we crossed the lawn in the direction of the workshop.

"We have only a short time at our disposal," whispered Forrest. "The darkness is lifting, and our friend will soon be returning."

We passed through a side door, which we found unlocked, into what had once been the stable-yard. But we could get no further. The two doors which gave admission to the building were firmly fastened, and there was no available window by which we might gain entrance. We retraced our steps, and, passing out of the door, approached the stables from the road. By this time the dawn had made such progress that we knew our chances of getting inside before Mannering's return were dwindling rapidly. We found no more likelihood of obtaining admission from this side than the other.

"I cannot arrest a man on the evidence of a few grains of tobacco dust, and an empty phial," declared Forrest, savagely, as he shook the tightly locked door. "Listen!" I said.

Borne on the wind came the throb of a motor. So still was the air that when the sound first reached our ears it must have been a mile away. The sound drew nearer and nearer, and while it was still a quarter of a mile distant, I recognized the familiar noise of Mannering's car, a sound as dissimilar to the hum of the Pirate car as it was possible to conceive.

"Forrest," I cried, turning to my companion, "we must be mad to think that Mannering could play the part of the Motor Pirate on that old car of his."

There was something so irresistibly ludicrous in the idea, that we both indulged in a hearty fit of laughter, and with one accord we turned and walked down the road.

"He may keep his fast car elsewhere," remarked the detective, when his mirth had subsided.

"It would be difficult to bring the guilt home to him if we failed to discover the car," I replied.

A few seconds later we met the man whom we had so lately suspected. I felt a tinge of shame at the thought that, a few minutes previously, I had been sneaking into his house in the hope that I should find evidence to convict him of a crime. By this time dawn was sufficiently advanced to allow of recognition, and as he came level with us Mannering pulled up.

"Hullo, Sutgrove!" he shouted. "You're about betimes. Been on the same job as myself?"

"What's that, Mr. Mannering?" asked Forrest

"Looking for an opportunity to pay back this little debt," was the light answer, as the speaker tapped his shoulder gently.

"Any luck?" said Forrest, dryly.

"Not a scrap," was the ready reply. "You see I'm a bit handicapped with this old car, for unless the fellow happens to take the same road as myself, there's precious little chance of my picking him up. Still, if you do not soon succeed in catching him, I think I shall have a good try myself."

"I suppose by that you know who he is," I remarked, more in order to see what he would say than in the hope of eliciting anything.

"Not the slightest idea on the subject," he responded promptly. "I am merely hoping that in a few days I shall be in possession of a new motor from which even the Pirate will be unable to escape."

I made a gesture of surprise.

"Fact," he continued. "My experiments have proved successful at last. In a week I shall have delivered to me the new motor I have designed, and then the Pirate had better look out. Good night."

Waving an adieu, he set his car in motion, and jogged along until he reached the door of his coach-house. We watched him dismount, unlock the door, and disappear inside.

"It beats me," remarked Forrest.

"Surely you do not still harbour any suspicion concerning him?" I inquired in amazement.

Forrest made no reply. His head was bent, his brow knitted deeply, his hands clasped behind him as we turned and walked back to my place. He did not speak until we stopped on my doorstep.

"I wish he had not seen us," my companion then remarked. "He will be bound to tumble to the conclusion that we suspect him, and will be on his guard."

"Then you do still suspect him," I cried again.

"If I had one scrap of direct evidence," replied the detective, emphatically, "I would have him under arrest within half an hour. Only one little scrap," he almost groaned. "But, as it is, my reputation would not survive if I made a mistake."

"Why, you don't imagine that he would go so far as to shoot himself just to avert suspicion," I asked, still incredulous.

Forrest drew himself up smartly. "Good Lord! What a fool I am! What—a—blind—dunderheaded—jackass!" he cried.

"What's the matter now?" I inquired smiling, for the detective was groping in his pockets. "Have you lost anything?"

From his waistcoat pocket he produced a small leaden bullet, and he held it outstretched in the palm of his hand.

"Here have I been wasting weeks on the continent, while with this I might have settled the matter once and for all."

"How?" I asked.

"I needed but to compare this with the bullet the surgeon extracted from Mannering's shoulder. This is the one which killed the poor fellow near Towcester. If Mannering's bullet is identical with this, I should have nothing more to say; but," he continued meaningly, "both your revolver and mine are of a different calibre to the weapon which fired this. If the bullet which hit Mannering should prove to fit either of our weapons, there would be no need to seek for further evidence. I must see that surgeon at once."

He started off rapidly down the garden path. I hurried after him and laid my hand on his arm.

"Steady, old man," I remarked. "You can hardly knock up a hardworked medical man at 3.30 a.m. just to ask him a question."

Forrest stopped and gave a short laugh. "Upon my word, I had entirely forgotten what the time was. No, you are quite right. There is no need for such excessive hurry. Mannering is safe enough for the present."

"At least, for the next eighteen hours," I observed, after glancing at my watch. "Meanwhile, your room has been kept ready for you."

"A little sleep will not come amiss," he answered, yawning; "though it seems almost a pity to go to bed on such a morning."

He was right. By this time dawn was breaking with a splendour I have never seen equalled before nor since. From east to west the sky was stained and flecked with crimson and gold, and our faces glowed ruddily in the reflected light. We both fell to silence, as with our faces to the east we watched the uprising of the sun; and, until the sky paled as the sun made its appearance above the line of the horizon, we did not stir.

Then Forrest drew a deep breath. "There's been the beauty of destruction in the sunrise," he remarked. "We shall have a storm before nightfall."

He followed me indoors, and, leaving him at the door of his room, I went to my own. I got into my pyjamas, but I did not feel inclined to sleep for the sunbeams were glancing in at my window, and all about were the sound and movement of the awakening earth-creatures. I wheeled an easy chair to the window, and wrapping a blanket about me, took a novel I had been reading and strove to fix my attention on the pages. I could not do so. Whether it was the reflex action of the brain from the excitement of the evening or not, but the fact was I felt unaccountably depressed. I fought against the feeling as best I could. But I could not get out of my head the idea that some great danger was threatening, not myself, but the one dearest to me in the world. From my window I could see her home, and I drew the chair into a position where my eyes might rest upon the roof which sheltered her. There was some consolation in this, and I watched until I eventually fell into an uneasy slumber, from which I awakened unrefreshed and ill at ease.