CHAPTER XXIX

  THE THEORY OF LING CHU

  Upon this scene came Ling Chu, imperturbable, expressionless, bringingwith him his own atmosphere of mystery.

  "Well," said Tarling, "what have you discovered?" and even Whitesidechecked his enthusiasm to listen.

  "Two people came up the stairs last night," said Ling Chu, "also themaster." He looked at Tarling, and the latter nodded. "Your feet areclear," he said; "also the feet of the small-piece woman; also the nakedfeet."

  "The naked feet?" said Tarling, and Ling Chu assented.

  "What was the naked foot--man or woman?" asked Whiteside.

  "It may have been man or woman," replied the Chinaman, "but the feet werecut and were bleeding. There is mark of blood on the gravel outside."

  "Nonsense!" said Whiteside sharply.

  "Let him go on," warned Tarling.

  "A woman came in and went out----" continued Ling Chu.

  "That was Miss Rider," said Tarling.

  "Then a woman and a man came; then the bare-footed one came, because theblood is over the first women's footmarks."

  "How do you know which was the first woman and which was the second?"asked Whiteside, interested in spite of himself.

  "The first woman's foot was wet," said Ling Chu.

  "But there had been no rain," said the detective in triumph.

  "She was standing on the grass," said Ling Chu, and Tarling nodded hishead, remembering that the girl had stood on the grass in the shadow ofthe bushes, watching his adventure with Milburgh.

  "But there is one thing I do not understand master," said Ling Chu."There is the mark of another woman's foot which I cannot find on thestair in the hall. This woman walked all round the house; I think shewalked round twice; and then she walked into the garden and through thetrees."

  Tarling stared at him.

  "Miss Rider came straight from the house on to the road," he said, "andinto Hertford after me."

  "There is the mark of a woman who has walked round the house," insistedLing Chu, "and, therefore, I think it was a woman whose feet were bare."

  "Are there any marks of a man beside us three?"

  "I was coming to that," said Ling Chu. "There is a very faint trace of aman who came early, because the wet footsteps are over his; also he left,but there is no sign of him on the gravel, only the mark of awheel-track."

  "That was Milburgh," said Tarling.

  "If a foot has not touched the ground," explained Ling Chu, "it wouldleave little trace. That is why the woman's foot about the house is sohard for me, for I cannot find it on the stair. Yet I know it came fromthe house because I can see it leading from the door. Come, master, Iwill show you."

  He led the way down the stairs into the garden, and then for the firsttime Whiteside noticed that the Chinaman was bare-footed.

  "You haven't mixed your own footmarks up with somebody else's?" he askedjocularly.

  Ling Chu shook his head.

  "I left my shoes outside the door because it is easier for me to workso," he said calmly, slipping his feet into his small shoes.

  He led the way to the side of the house, and there pointed out thefootprints. They were unmistakably feminine. Where the heel was, was adeep crescent-shaped hole, which recurred at intervals all round thehouse. Curiously enough, they were to be found in front of almost everywindow, as though the mysterious visitor had walked over the gardenborder as if seeking to find an entrance.

  "They look more like slippers than shoes to me. They're undoubtedly awoman's," said Whiteside, examining one of the impressions. "What do youthink, Tarling?"

  Tarling nodded and led the way back to the room.

  "What is your theory, Ling Chu?" he asked.

  "Somebody came into the house," said the Chinaman, "squeezed through thedoor below and up the stairs. First that somebody killed and then went tosearch the house, but could not get through the door."

  "That's right," said Whiteside. "You mean the door that shuts off thislittle wing from the rest of the house. That was locked, was it not,Tarling, when you made the discovery?"

  "Yes," said Tarling, "it was locked."

  "When they found they could not get into the house," Ling Chu went on,"they tried to get through one of the windows."

  "They, they?" said Tarling impatiently. "Who are they? Do you mean thewoman?"

  The new theory was disturbing. He had pierced the second actor in thetragedy--a brown vitriol burn on the back of his hand reminded him of hisexistence--but who was the third?

  "I mean the woman," replied Ling Chu quietly.

  "But who in God's name wanted to get into the house after murdering Mrs.Rider?" asked Whiteside irritably. "Your theory is against all reason,Ling Chu. When a person has committed a murder they want to put as muchdistance between themselves and the scene of the crime as they can in theshortest possible space of time."

  Ling Chu did not reply.

  "How many people are concerned in this murder?" said Tarling. "Abare-footed man or woman came in and killed Mrs. Rider; a secondperson made the round of the house, trying to get in through oneof the windows----"

  "Whether it was one person or two I cannot tell," replied Ling Chu.

  Tarling made a further inspection of the little wing. It was, as Ling Chuhad said and as he had explained to the Chinaman, cut off from the restof the house, and had evidently been arranged to give Mr. Milburgh thenecessary privacy upon his visits to Hertford. The wing consisted ofthree rooms; a bedroom, leading from the sitting-room, evidently usedby Mrs. Rider, for her clothes were hanging in the wardrobe; thesitting-room in which the murder was committed, and the spare roomthrough which he had passed with Odette to the gallery over the hall.

  It was through the door in this room that admission was secured to thehouse.

  "There's nothing to be done but to leave the local police in charge andget back to London," said Tarling when the inspection was concluded.

  "And arrest Milburgh," suggested Whiteside. "Do you accept Ling Chu'stheory?"

  Tarling shook his head.

  "I am loath to reject it," he said, "because he is the most amazinglyclever tracker. He can trace footmarks which are absolutely invisibleto the eye, and he has a bushman's instinct which in the old days inChina led to some extraordinary results."

  They returned to town by car, Ling Chu riding beside the chauffeur,smoking an interminable chain of cigarettes. Tarling spoke very littleduring the journey, his mind being fully occupied with the latestdevelopment of a mystery, the solution of which still evaded him.

  The route through London to Scotland Yard carried him through CavendishPlace, where the nursing home was situated in which Odette Rider lay. Hestopped the car to make inquiries, and found that the girl had recoveredfrom the frenzy of grief into which the terrible discovery of the morninghad thrown her, and had fallen into a quiet sleep.

  "That's good news, anyway," he said, rejoining his companion. "I was halfbeside myself with anxiety."

  "You take a tremendous interest in Miss Rider, don't you?" askedWhiteside dryly.

  Tarling brindled, then laughed.

  "Oh, yes, I take an interest," he admitted, "but it is very natural."

  "Why natural?" asked Whiteside.

  "Because," replied Tarling deliberately, "Miss Rider is going to be mywife."

  "Oh!" said Whiteside in blank amazement, and had nothing more to say.

  The warrant for Milburgh's arrest was waiting for them, and placed in thehands of Whiteside for execution.

  "We'll give him no time," said the officer. "I'm afraid he's had a littletoo much grace, and we shall be very lucky if we find him at home."

  As he had suspected, the house in Camden Town was empty, and the womanwho came daily to do the cleaning of the house was waiting patiently bythe iron gate. Mr. Milburgh, she told them, usually admitted her athalf-past eight. Even if he was "in the country" he was back at the housebefore her arrival.

  Whiteside fitted a skeleton key into the lock o
f the gate, opened it (thecharwoman protesting in the interests of her employer) and went up theflagged path. The door of the cottage was a more difficult proposition,being fitted with a patent lock. Tarling did not stand on ceremony, butsmashed one of the windows, and grinned as he did so.

  "Listen to that?"

  The shrill tinkle of a bell came to their ears.

  "Burglar alarm," said Tarling laconically, and pushed back the catch,threw up the window, and stepped into the little room where he hadinterviewed Mr. Milburgh.

  The house was empty. They went from room to room, searching the bureauxand cupboards. In one of these Tarling made a discovery. It was no morethan a few glittering specks which he swept from a shelf into the palm ofhis hand.

  "If that isn't thermite, I'm a Dutchman," he said. "At any rate, we'll beable to convict Mr. Milburgh of arson if we can't get him for murder.We'll send this to the Government analyst right away, Whiteside. IfMilburgh did not kill Thornton Lyne, he certainly burnt down the premisesof Dashwood and Solomon to destroy the evidence of his theft."

  It was Whiteside who made the second discovery. Mr. Milburgh slept on alarge wooden four-poster.

  "He's a luxurious devil," said Whiteside. "Look at the thickness of thosebox springs." He tapped the side of that piece of furniture and lookedround with a startled expression.

  "A bit solid for a box spring, isn't it?" he asked, and continued hisinvestigation, tearing down the bed valance.

  Presently he was rewarded by finding a small eyelet hole in the side ofthe mattress. He took out his knife, opened the pipe cleaner, and pressedthe narrow blade into the aperture. There was a click and two doors,ludicrously like the doors which deaden the volume of gramophone music,flew open.

  Whiteside put in his hand and pulled something out.

  "Books," he said disappointedly. Then, brightening up. "They are diaries;I wonder if the beggar kept a diary?"

  He piled the little volumes on the bed and Tarling took one and turnedthe leaves.

  "Thornton Lyne's diary," he said. "This may be useful."

  One of the volumes was locked. It was the newest of the books, andevidently an attempt had been made to force the lock, for the hasp wasbadly wrenched. Mr. Milburgh had, in fact, made such an attempt, but ashe was engaged in a systematic study of the diaries from the beginning hehad eventually put aside the last volume after an unsuccessful effort tobreak the fastening.

  "Is there nothing else?" asked Tarling.

  "Nothing," said the disappointed inspector, looking into the interior."There may be other little cupboards of this kind," he added. But a longsearch revealed no further hiding-place.

  "Nothing more is to be done here," said Tarling. "Keep one of your men inthe house in case Milburgh turns up. Personally I doubt very much whetherhe will put in an appearance."

  "Do you think the girl has frightened him?"

  "I think it is extremely likely," said Tarling. "I will make an inquiryat the Stores, but I don't suppose he will be there either."

  This surmise proved to be correct. Nobody at Lyne's Store had seen themanager or received word as to his whereabouts. Milburgh had disappearedas though the ground had opened and swallowed him.

  No time was lost by Scotland Yard in communicating particulars of thewanted man to every police station in England. Within twenty-four hourshis description and photograph were in the hands of every chiefconstable; and if he had not succeeded in leaving the country--which wasunlikely--during the time between the issue of the warrant and hisleaving Tarling's room in Hertford, his arrest was inevitable.

  At five o'clock that afternoon came a new clue. A pair of ladies' shoes,mud-stained and worn, had been discovered in a ditch on the Hertfordroad, four miles from the house where the latest murder had beencommitted. This news came by telephone from the Chief of the HertfordConstabulary, with the further information that the shoes had beendespatched to Scotland Yard by special messenger.

  It was half-past seven when the little parcel was deposited on Tarling'stable. He stripped the package of its paper, opened the lid of thecardboard box, and took out a distorted-looking slipper which had seenbetter days.

  "A woman's, undoubtedly," he said. "Do you note the crescent-shapedheel."

  "Look!" said Whiteside, pointing to some stains on the whitey-brown innersock. "That supports Ling Chu's theory. The feet of the person who worethese were bleeding."

  Tailing examined the slippers and nodded. He turned up the tongue insearch of the maker's name, and the shoe dropped from his hand.

  "What's on earth the matter?" asked Whiteside, and picked it up.

  He looked and laughed helplessly; for on the inside of the tongue was atiny label bearing the name of a London shoemaker, and beneath, writtenin ink, "Miss O. Rider."