the inspector stood there with his hand on his heart, as if he had run far and fast. so far as jack could see, bates was suffering from some strong emotion. he flopped down in the chair indicated for him, and took jack's proffered cigarette with a shaking hand. although his feelings were not exactly under the control one would have expected from one of the leading lights of scotland yard, there was at the same time a certain suggestion of grim humor playing about the corners of his mouth. jack looked across at rigby and smiled significantly.

"evidently a new development of the case," jack said, glancing once more at his friend. "as a matter of fact, inspector, i have just been telling mr. rigby all about last night's ghastly business. by the way, you will recollect, of course, that mr. rigby is my friend whom we met at mr. carrington's last night. not to make too long a story of it, there are sidelights of this business of which you are not at present aware--but all that is beside the point. what i want you to tell me is about this disappearance of the body of nostalgo. seriously, do you want my friend and me to believe that the body of a dead man has disappeared from shannon street police station right under the eyes of the authorities?"

"well, that is about the size of it," bates admitted ruefully. "naturally enough, we look forward to important developments at the official inquiry. i had a chat late last night with the doctor, who seemed to be of the opinion that the dead man had been shot with something quite new in the way of a weapon."

"what, do you mean a new projectile or a new sort of small arm?" masefield asked.

"well, not exactly that," the inspector replied; "but something quite new in the way of a missile. there were marks on the breast of our unfortunate friend which indicated the presence of a shot of some kind that did mortal damage without leaving traces of anything material behind."

"oh, that is all very well, so far as it goes; but what i want to get at chiefly is the cause of the disappearance of the body," rigby put in impatiently. "what is the good of trying to establish all sorts of new theories when you have not so much as a dead body of the deceased man before you? it seems incredible to me that this outrage could have been committed in a police station. was no one about--was the whole place deserted, whereby some stranger could have coolly stepped in and walked off with the body of a powerful man?"

"well, that is not so difficult as it might seem," bates said eagerly. "as a matter of fact, our mortuary is merely an outside room which at one time had been used as a kitchen. mr. masefield will recollect last night noticing that the light of the room consisted entirely of a kind of skylight. the ceiling is exceedingly low, so that it would be quite possible for a tall man to lift the body through and carry it away without the least trouble, provided, of course, that he had sufficient strength. at any rate, there it is, and we have to make the best of it."

"i hope that you have managed to keep this matter from the public so far," masefield said. "i don't think anything will be gained by allowing this new sensation to get into the papers. the best thing we can do is to come round to shannon street with you and see if we can lay our hands upon anything in the way of a clue. my friend mr. rigby has had a lot of experience in amateur detective work; i dare say you recollect his success in the matter of the mortlake coiners, on behalf of the planet."

bates expressed his willingness to fall in with this arrangement. not that he had any particular confidence in amateur detectives generally; but he was so bewildered and disheartened at present that anything was preferable to his own painful thoughts. the police station was reached at length, and a thorough search of the shabby little apartment at the back of the office made. but no amount of investigation served to throw any light on this new phase of the mystery. it was even as bates had said: with the darkness of the night, and expecting no developments of this kind, a bold and unscrupulous character might easily have entered the room and taken away anything, however bulky, without much chance of detection.

nothing daunted by the want of success attending his efforts, rigby climbed on to the roof and looked around him. he was particularly struck by the deserted area at the back of the police station. it was some distance from his coign of vantage to the nearest house. no doubt at one time the open space had consisted of fertile gardens, but the same space was now given over to arid grass and a few stunted trees--a scene of desolation indeed. on the opposite side, some two hundred yards away, the backs of a terrace of large houses looked blankly on the scene. rigby, with a new idea entirely in his mind, inquired the name of the terrace. bates smiled with the superior air of the professional, and replied that it was montrose place.

"and what class of people live there?" rigby asked.

"well, rather mixed, i should say," bates replied. "there was a time, not so many years ago, when montrose place was quite fashionable. mind you, they're exceedingly good houses, quite good enough for any moneyed class; but i understand that the landlord is by no means a liberal man, and, as the houses have fallen out of repair, they have become void."

any further information on this head was cut short by the sudden calling away of the inspector. it seemed to masefield that rigby was by no means disposed to mourn for the official's company. he stood with his brows bent frowning at the sombre row of houses in front of him, but, from the quick working of his hands, masefield could see that his versatile friend's brain was busy.

"i see you have made a discovery," masefield said quietly. "would you mind telling me what it is?"

rigby pointed to the fourth house from the end of the terrace. did masefield notice anything about it peculiar? he asked. but masefield did not see anything about the house at all ominous or suggestive, except that the windows were grimy and dirty, and that the erstwhile fashionable silk blinds were hanging in tatters like banners behind the murky glass.

"but surely you see something?" asked rigby impatiently. "for instance, take the third window on the left over the ledge, which probably is that of the bathroom. don't appear to be looking, and, at the same time, keep your eye casually on the window."

with a quickening of his pulses, masefield glanced up in a vague kind of way in the direction of the window. he felt instinctively that in some way the deserted house was involved in the disappearance of nostalgo. there was not much time for speculation on this point. very slowly and cautiously the blind was raised, and a haggard face peeped out. it was like a picture from some old print, this strange weird yellow face behind the grimy glass. so thick was the murky dust upon the casement that it was impossible at so short a distance to decide whether the features were those of a man or a woman. anyway, the face, if it were that of a man, was clean-shaven, the pale head half hidden behind a tangle of thick black hair. it was only for a moment that this weird face presented itself to the eager eyes of the spectators below; an instant later and the whole phantom had vanished.

"now, what do you think of that?" rigby asked eagerly. "don't you agree with me that this strange apparition has something to do with the story? now, supposing you or i had some powerful inducement for getting hold of the missing body, could we find a better place to work from than that deserted house?"

"provided always that it is deserted," masefield said guardedly. "don't let's go quite so fast. surely your own experience must have taught you what strange creatures one often sees as caretakers in good houses?"

"so much the better for me," rigby replied. "if you are correct in your suggestion, it will make my task all the more easy; for, come what may, i am going to see the whole inside of that place before i sleep to-night."

rigby walked back into the police station with the air of a man who has said his last word on the matter. it was no advantage to him, working as he was on behalf of his own newspaper, to mention his discovery to bates. possibly masefield's common-sense view of the problem might have been the correct one, after all, in which case bates would have had the laugh of his unprofessional ally. but bates had evidently been called out on other business, so that there was no occasion to say anything to him at all. declining to return to masefield's rooms and there discuss the matter further over tea, rigby went thoughtfully back to the office of the planet. he dined alone at his club, lingering till about ten o'clock over the evening papers, and then proceeded on his way to montrose place by the somewhat circuitous route of covent garden.

but there was more method in rigby's madness than met the eye. the sleek, well-groomed barrister and journalist who entered the shop of jonas the costumier shortly after ten o'clock, emerged a little before eleven carefully and effectually disguised as a seller of newspapers. then, with the fag-end of a cigarette of doubtful quality in his mouth, he slouched along towards his destination.

montrose place from a front view was considerably more prepossessing than the similar outlook that presented itself from the back. at least half the houses were tenanted by people of means, judging from the neatness of the blinds and the amount of light displayed in the various windows. yet, at the same time, it was quite evident that bates' estimate was fairly correct.

the first three houses in the terrace bore plates of highly polished brass, testifying to the fact that doctors were not lacking in the locality. no. 4, however, stood out in marked contrast to its neighbors. there was no chance of rigby's presence there exciting undue suspicion, for there was not a soul to be seen in the terrace.

emboldened by this fact, rigby had no hesitation in lighting a vesta and making a comprehensive examination of the door-steps. they were dirty enough in all conscience; no housemaid had knelt there for many months or even years past; but rigby's sharp eyes did not fail to note the fact that some one more than once recently had left footprints on the grimy flags. they were not dearly indented footprints; indeed, there was a misty hesitation about them which at first puzzled the amateur detective exceedingly.

he struck another match after looking cautiously up and down the terrace. nobody was in sight; the precaution was quite unnecessary; the blue flame picked out the misty footprints grimed into the filthy steps, and then rigby understood. whoever made those marks had been wearing rubber-soled shoes.

"and new shoes at that," rigby muttered to himself. "i can see the pattern in the centre of the sole clearly indented now. and the prints go and come up and down the steps quite regularly. now, the fact that somebody comes here and wears new rubber shoes makes it clear that the wearer has been here very recently. it is also evident that the wearer wears rubber-soled tennis shoes so as to make no noise. i feel pretty certain that i am going to learn something now."

but rigby was a little too sanguine. in the first place, he had to gain admission to the house, the front door of which was locked. it was perhaps a significant fact that, though the lock of the door was green with rust, the edge of the rim of the hole where the latch-key indented was bright and clear at the edges.

"evidently used regularly," rigby went on. "now, the ordinary caretaker does not usually sport a latch-key; he or she generally uses the area door. i should not wonder if the area window was open; i'll try it."

the area window was not open, but the loose catch had been carelessly pushed to. the blade of a stout penknife sufficed to prize the catch, and a moment later rigby was in the housekeeper's room, safe from all outside observation.

there was no sign of life here; no vestige of it on the stairs leading to the big rooms overhead. rigby could not but notice what a fine house it was; the last tenant had evidently been lavish in the way of decorations. with a match in his hand carefully shaded from the window, rigby crept up the stairs. he could see in the dust lying there the constantly repeated footprint of the rubber shoe, indicating that the owner of that shoe was in the habit of spending a great deal of time there.

but now, so far as he could judge, the house was absolutely deserted. he tried door after door softly, and each yielded to his touch, revealing gloom and desolation and dirt by the faint light of the vesta. as each stump burned low rigby carefully dropped the end of it in his pocket. he was conscious of a feeling of disappointment. almost before he was fully cognizant of that feeling he paused in an attitude of rigid attention. something like the sound of a smothered cough struck on his ear; it seemed to him that he could hear somebody approaching. the stair creaked, and rigby drew back into a doorway.

he was not mistaken. somebody was coming up the stairs.