Perhaps this place in Mynden Street was not his home but merely a retreat , used for the purpose of disguise ?sx It was an old trick , one which Blackshirt had once practised himself until he found the flat in Notting Hill which served him so well .sx In which case it was not unlikely that the man's horsey , rat-like appearance was a clever disguise !sx Verrell became curious about the door still open through which his quarry had disappeared .sx Then he began to wonder why the front door should be left open , but as he glanced at the house nearest him he saw that , already small enough in all conscience , it was split into that type of upstairs and downstairs flat forced upon an unwilling people by economic reasons .sx Thus the one front door , which had to serve both flats , was left open for the benefit of visitors .sx Suddenly Verrell chuckled slightly as a daring suggestion occurred to him :sx why should he not be a visitor , and penetrate into the interior of the house in the hope of finding out more of the detective ?sx Of course , there was a certain risk attached ; the man might take it into his head to step out again and meet Verrell face to face , after which there would be no further doubt in his mind that Verrell and Blackshirt was the same man .sx Nevertheless , he decided to chance it , so pulling his hat down over his eyes , he proceeded along the road and unhesitatingly entered Number Seventeen .sx Nobody was to be seen , although he heard voices in the room to the left of him .sx The faint whispering echo made him realise that he had yet to find whether the detective occupied the ground floor flat or the one above .sx Casually he approached the door through which he heard the sound of people talking , and although , because of the open door , he dared notstand still , obviously listening , he heard enough to make him rest assured that there were no men present in the room .sx He quietly mounted the staircase .sx Upstairs it was fortunately dim , for all doors were shut , and only the light from downstairs was reflected .sx Before him there were three doors , but he had no need to ask behind which one was the detective :sx once again an unintelligible murmur of voices guided him .sx He stepped up close to the door , and , to his immense delight , he realised that he was able to distinguish what was being said .sx " Garn !sx Bill , of course yer on the wrong track .sx 'Aven't I already told yer onct to-day that 'e couldn't 'ave got out of that there flat of his without me a-knowing of it ?sx Gawd's strewth , I didn't 'ave a drop , Bill , I wouldn't go back on you .sx " Despite the words being uttered in a kind of whining appeal , there seemed a certain depth of feeling behind them , and as far as the listener outside was concerned , he was ready to believe the man , though as yet he did not know the drift of the conversation .sx Bill likewise seemed prepared to accept the truth of the statement .sx " I know you wouldn't , old man .sx Yer an old sport in yer own way , but what's to prevent 'im having a back way what you weren't able to see ?sx He's cunning enough for it .sx " " Yes , I s'pose so :sx I didn't think of that .sx " " I didn't think you would .sx Still , now you see what I'm a-getting at :sx I've got 'im good and proper this time .sx 'E's after them jools all right , what was stolen from the girl's bedroom .sx Now it weren't the policeman as took them , or this 'ere fireman what's in all the papers to-day .sx If it weren't either of them two , who was it ?sx " .sx Outside the room Verrell grinned to himself ; if .sx the man Bill could answer his own question then he was cleverer than Blackshirt himself .sx " I don't know .sx " " Why , that blinking rotter of a uncle of hers , of course , you blockhead !sx " .sx Verrell barely repressed a gasp of astonishment .sx Ye Gods !sx Bill was right ; the man had alighted on the one possible suspect to whom he himself had never given a second's thought .sx Betty's uncle !sx Flashingly he realised that it was all due to the uncle that he had set out on a trail which , so far , had led nowhere .sx It was Warrington who had stated that the policeman and fireman were the only ones to enter Betty's bedroom .sx Doubtless he had told the truth up to the point !sx Seeing the opportunity to push the blame of the theft on to other shoulders , he had not only seized Betty's jewels , which he had so long cherished , but all the other jewellery which Blackshirt had returned to her .sx It was a cunning scheme and one worthy of the grasping old scoundrel .sx Furious with himself for not having suspected Warrington in the first place , he grimly assured himself that he would have the pleasure of making the uncle suffer twice over for every humiliation he had caused his niece .sx Meanwhile , he listened at the door of Bill's room , conscious of a deeper respect for the puny detective , whose powers he had undoubtedly under-estimated .sx " He's the sort of swine who 'udd do the dirty on a girl .sx You bet he's had a hand in pinchin' them jools .sx ' " Yus , " Fred said slowly , " but what's that to do wif you 'aving 'im by the shorts ?sx " .sx " You do think fast , I don't think , Fred , " Bill explained patiently .sx " I've enough respect for Blackshirt to guess that he's already on Warrington's .sx track .sx What's he goin' ter do about it ?sx Why , sooner or later he's goin' to break into the Warrington house for the second time , and next time " even through the door Verrell distinctly heard him close his mouth with a snap " I'll get him good and proper or throw myself in the ruddy old Thames .sx " " What's the programme ?sx " .sx " You keep watch at night as usual , Fred .sx I'm going to take a chance and leave off watching Mr. Blooming Verrell by day .sx Every night from to-night onwards I'm going to hide in that there coal-cellar wot's in the area .sx I'll wait until Blackshirt comes along after Warrington's blood , and I'll snaffle him good and proper and perhaps the jools as well , " he finished , chuckling .sx " That's the idea , " applauded his brother .sx " All Sir John cares about is the arrest of Blackshirt , ain't it ?sx " .sx " Yus , and I'm going to give 'im a pleasant surprise , before very long , or me name ain't William Harris .sx So long , Fred , keep on the watch to-night .sx I'm going to scent around Argyll Road meanwhile .sx " Verrell moved with lightning-like rapidity , but even so he was scarcely out of the front door before Harris reached the top of the stairs .sx However , keeping watch from round a nearby corner , as far as he could see the detective was unsuspicious of the fact that his conversation had been overheard .sx Once Harris was well away he made for home , extraordinarily relieved by the knowledge that meanwhile , if only for a short period , nobody was dogging his footsteps .sx During the next few days , while Harris slept the day through ready for his night watch , Verrell .sx traversed all the streets in the neighbourhood in which the Warringtons lived , a double purpose in mind .sx In the first case he wanted to familiarise himself once again with the local topography , and secondly , he wanted to evolve a plan to circumvent Harris .sx So , while he paced the streets , busily noting every turning , every corner , and every tree and hedge , he thought of and rejected plan after plan .sx It was not until the morning of the fifth day the first germ of an idea occurred to him , but by the evening it was perfected .sx For the seventh night in succession Harris crept to his uncomfortable bedroom , cursing the day Sir John Wakefield had first made use of his services .sx Of course , he was receiving good money from Sir John , but he was earning every penny of it , and consequently Harris was more or less dissatisfied .sx His idea of life was to do very little for a good deal of pay .sx Meanwhile the detective endeavoured to arrange the coal so that too many knobs did not stick into him as he tried to lie down and P.C. Wilson patrolled his beat , contented that the night was dry and warmish .sx Presently one o'clock struck ; just a minute later the constable rounded the corner of Midas Road , and from out of the shadows appeared the vague figure of a man .sx " Constable , I am Marshall of the C.I.D. , " the shadow announced itself .sx " There's a big stunt on to-night :sx ever heard of Blackshirt ?sx The man had heard vague rumours in police circles of the cracksman .sx He nodded his head .sx " Yes .sx " " Well , we have just had a good tip that he is pulling off a job somewhere on your beat .sx Now listen carefully .sx Keep a good look out , and if you see anything of him , don't go rushing after him .sx The Commissioner has his own pet plans all set , and there are apt to be ructions if anything goes wrong with them .sx You understand ?sx " .sx " Yes , sir .sx What am I to do , then ?sx " Directly you see this fellow Blackshirt , chase off and get Johnson from the next beat .sx Set him to keep an eye on whatever house you see this man in , then go quietly to 61 , Argyll Road , and in the coal-cellar down the area you will find Detective-Sergeant Harris of the C.I.D. Tell him you have seen Blackshirt ; after that , it will be up to you and him to make an arrest .sx I'll be near to cut in if anything goes wrong .sx Got all that ?sx " .sx " Yes , sir .sx " " Good .sx " The shadow disappeared silently into the night .sx Wilson pushed his helmet back a little .sx " Well , I'll be blowed !sx " he ejaculated to himself .sx " Good man , Marshall , so I've heard .sx Due to retire soon .sx Hope I claps hands on this here Blackshirt " and muttering to himself he paced slowly up Midas Road .sx Verrell watched him disappearing .sx " You are young and innocent , my lad !sx So much the better , " and he chuckled quietly .sx " Now for it .sx " With that he vaulted over a low fence .sx Once safely on the other side he pulled off his one-piece dickey , tie and collar , underneath which he wore his black shirt .sx Next he adjusted his hood , and donned his gloves .sx He was ready to put his scheme into action , a scheme which he had planned with meticulous care , and which depended upon the .sx perfect working out of a scrupulously arranged time-table .sx From the shelter of the fence he pulled out a bicycle to which he had helped himself earlier in the evening .sx He lifted it over the fence , and carried it across the road to the house opposite , which had a garage built out from it .sx Once again he hid the machine , this time behind the well-trimmed hedge which surrounded the small garden alongside the garage .sx Again he crossed the road to the back garden in which he had originally hidden the bicycle .sx From the same place he extracted two bags , one fairly small , the other larger .sx Observing that the streets were as silent as the grave , he walked some distance until he reached his destination , a small house , empty for the week-end .sx He had no difficulty in obtaining an entrance to one of the front rooms , where he placed the two bags .sx Next he opened the door which led to the back , and finally the back door itself , which gave on to a small garden .sx This done he returned to the front room .sx More than thirty minutes had passed , and although he had kept a strict watch , P.C. Wilson had seen nothing to give rise to any suspicions .sx Then , just when he had begun to think nothing was likely to happen , he saw , in the garden of a house some way ahead of him on the other side of the road , a momentary flash of light .sx The next moment all was dark again .sx Nevertheless , it had been sufficient to put him on the qui vive .sx He remained perfectly still , watching .sx For another minute nothing happened ; then he saw the flash again .sx