Just as Markham and Heath and I turned to follow Vance, there came, from somewhere outside, a startling and ominous rattle that sounded like the staccato and rapid sputtering of a machine-gun. So keyed up were my nerves that the reports went through me with a sickening horror, almost as if it had been the bullets themselves.

    "God Almighty!" came the explosive exclamation of the Sergeant, who was at my side; and he stopped abruptly, as if he, too, had been struck by a bombardment of bullets. Then he suddenly sprang forward past Vance and, jerking the front door open, hurried out into the warm summer night without a word to any one. The rest of us followed close behind him. The Sergeant had halted at the edge of the stone pathway to the sidewalk and was looking confusedly up and down the street, uncertain which way to turn. Guilfoyle had jumped down from his seat in the cab as we came out of the vestibule, and was gesticulating excitedly in front of Heath.

    "The shots came from up that way," he told Heath, waving his arm toward Central Park West. "What do you want me to do, Sarge?"

    "Stay here and keep your eyes open," Heath ordered in clipped accents, "until Sullivan and Hennessey arrive. . . . And," he added as he started off toward the park, "stick around after that, in case of any emergency."

    "I'm wise," Guilfoyle called after him.

    Guilfoyle saluted half-heartedly, as Markham and Vance appeared on the sidewalk, and again he waved his arm to indicate, I presume, which way Heath had gone. He leaned reluctantly against his cab as we followed the Sergeant up the street.

    "No," murmured Vance as we hurried along, "not a pleasant case. . . . And if my intuition is correct, these shots are another manifestation of its complexity."

    Heath was now breaking into a run ahead of us; and Markham and I had difficulty keeping pace with Vance as he, too, lengthened his stride.

    Just this side of the Nottingham Hotel at the corner, a small group of excited men were gathered under the bright light of the lamppost set between two trees along the curb. As Heath came abreast of the cluster of onlookers we could hear his gruff voice ordering them to disperse, and one by one they reluctantly moved off. Some continued on whatever business they had been about, while others remained to look on from the opposite side of the street. In the few moments it took us to reach the lamppost, the Sergeant had succeeded in clearing the scene.

    There, leaning in a crouching attitude against the iron lamppost, was Fleel. His face was deathly pale. I have yet to see so unmistakable a picture of collapse from fright as he presented. His nerves were completely shattered. He was as pitiful a figure as I have ever looked at, huddled beneath the unflattering glare of the large electric light overhead, as he leaned weakly for support against the lamppost. In front of the lawyer stood Quaggy, looking at him with a curious hard-faced serenity.

    Heath was staring at Fleel with a startled, inquisitive look in his eyes; but before he could speak to Fleel, Vance took the man under the arms and, knocking his feet from under him, set him down gently on the narrow strip of lawn which bordered the sidewalk, with his back against the lamppost.

    "Breathe deeply," Vance advised the lawyer, when he had settled him on the ground. "And pull yourself together. Then see if you can tell us what happened."

    Fleel looked up, his chest rising and falling as he sucked in the stagnant air of that humid July night. Slowly he struggled to his feet again and leaned heavily against the post, his eyes fixed before him.

    Quaggy put a hand on the man's shoulder, as if to steady him, and shook him gently as he did so.

    Fleel managed a sickly grimace intended for a smile, and turned his head weakly back and forth, blinking his eyes as if to clear his vision.

    "That was a close call," he muttered. "They almost got me."

    "Who almost got you, Mr. Fleel?" asked Vance.

    "Why—why—" the man stammered, and paused for breath. "The men in the car, of course. I—didn't see—who they were—"

    "Try to tell us, Mr. Fleel," came Vance's steadying voice, "just what happened."

    Fleel took another deep breath and, with an obvious effort, straightened up a little more.

    "Didn't you see it all?" he asked, his voice high and unnatural. "I was on my way to the corner, to get a taxicab, when a car drove up from behind me. I naturally paid no attention to it until it suddenly swerved toward the curb and stopped with a screeching of brakes, just as I reached this street light. As I turned round to see what it was, a small machine-gun was thrust over the ledge of the open window of the car and the firing began. I instinctively grasped this iron post and crouched down. After a number of shots the car jerked forward. I admit I was too frightened to notice which way it turned."

    "But at least you were not hit, Mr. Fleel."

    The man moved his hands over his body.

    "No, thank Heaven for that," he muttered.

    "And," Vance continued, "the car couldn't have been over ten feet away from you. A very poor shot, I should say. You were lucky, sir, this time." He spun round quickly to Quaggy, who had taken a step or two backward from the frightened man. "I don't quite understand your being here, Mr. Quaggy. Surely, you've had more than ample time to ensconce yourself safely in your boudoir."

    Quaggy stepped forward resentfully.

    "I was in my apartment. As you can see,"—he pointed indignantly to his two open front windows in the near-by hotel—"my lights are on. When I got to my rooms I didn't go directly to bed—I hope it wasn't a crime. I went to the front window and stood there for a few minutes, trying to get a breath of fresh air. Then I caught sight of Mr. Fleel coming up the street—he had apparently just left the Kenting house—and behind him came a car. Not that I paid any particular attention to it, but I did notice it. Only, when it turned in to the curb and stopped directly opposite Mr. Fleel as he reached the light post my curiosity was naturally aroused. And when I heard the machine-gun and saw the spits of fire coming through the window, and also saw Mr. Fleel grasp the lamppost and sink down, I thought he had been shot. I naturally dashed down—so here I am. . . . Anything illegal in that procedure?" he asked with cold sarcasm.

    "No—oh, no," smiled Vance. "Quite normal. Far more normal, in fact, than if you had gone immediately to bed without a bit of airin' by the open window." He glanced at Quaggy with an enigmatical smile. "By the by," he went on, "did you, by any chance, note what type of car it was that attacked Mr. Fleel?"

    "No, I didn't get a very good look at it," Quaggy returned in a chilly tone. "At first I didn't pay much attention to it, as I said; and when the shooting began I was too excited to get any vivid impression. But I think it was a coupé of some kind—not a very large car, and certainly not a new model."

    "And the color?" prompted Vance.

    "It was a dingy, nondescript color." Quaggy narrowed his eyes, as if trying to recall a definite picture. "It might have been a faded green—it was hard to be certain from the window. In fact, I think it was green."

    Heath was watching Quaggy shrewdly.

    "Yeah?" he said skeptically. "Which way did it go?"

    Quaggy turned to the Sergeant.

    "I really didn't notice," he replied none too cordially. "I caught only a glimpse of it as it started toward the park."

    "A fine bunch of spectators," Heath snorted. "I'll see about that car myself." And he started running toward Central Park West.

    As he neared the corner, a burly figure in uniform turned suddenly into 86th Street from the south, and almost collided with the Sergeant. By the bright corner light I could see that the newcomer was McLaughlin, the night officer on duty in that section, who had reported to us the morning of Kaspar Kenting's disappearance. He drew up quickly and saluted with a jerk.

    "What was it, Sergeant?" His breathless, excited query carried down to us. "I heard the shots, and been trying to locate 'em. Did they come outa this street?"

    "You're damn tootin', McLaughlin," replied Heath, and, grasping the officer by the arm, he swung him about, and the two started off again.

    "Did you see any car come out of this street, into Central Park West?" demanded Heath.

    I could not now hear what the officer answered, but when the two had reached the curb at the corner McLaughlin was waving his arm uptown, and I assumed that he was pointing in the direction that the green coupé had taken.

    Heath looked up and down the avenue for a moment, no doubt trying to find a car he could requisition for the chase; but there was apparently none in sight, and he started diagonally across the street uptown, with McLaughlin at his heels. In the middle of the crossing the Sergeant turned his head and called out over his shoulder to us:

    "Wait here at the corner for me." Then he and McLaughlin disappeared past the building on the north corner of Central Park West.

    "My word, such energy!" sighed Vance when Heath and the officer were out of sight. "The coupé could be at 110th Street by this time—and thus the mad search would end. Heath is all action and no mentation. Sad, sad. . . . Vital ingredient of the police routine, I imagine—eh, what, Markham?"

    Markham was in a solemn mood, and took no offense at Vance's levity.

    "There's a taxicab stand just a block up on Central Park West," he explained patiently. "The Sergeant is probably headed for that in order to commandeer a cab for the chase."

    "Marvellous," murmured Vance. "But I imagine even the green coupé could outrun a nocturnal taxi-cab if they both started from scratch."

    "Not if the Sergeant were to puncture one of its rear tires with a bullet or two," retorted Markham angrily.

    "I doubt if the Sergeant will have the opportunity, by this time." Vance smiled despondently. Then he turned to Fleel. "Feeling better?" he asked pleasantly.

    "I'm all right now," the lawyer returned, taking a wobbly step or two forward and biting the end from a cigar he took from his pocket.

    "That's bully," Vance said consolingly. "Do you want an escort home?"

    "No, thanks," said Fleel, in a voice that was still dazed. "I'll make it all right." And when he had his cigar going he turned shakily toward Central Park West. "I'll pick up a taxicab." He held out his hand to Quaggy, who took it with surprising cordiality. "Many thanks, Mr. Quaggy," he said weakly and, I thought, a little shamefacedly. Then he bowed somewhat stiffly and haughtily to us and moved away out of the ring of light.

    "Queer episode," commented Vance, as if to himself. "Fits in rather nicely, though. Lucky for your lawyer friend, Markham, that the gentleman in the green coupé wasn't a better shot. . . . Ah, well, we might as well toddle to the corner and await the energetic Sergeant. Really, y' know, Markham, there's no use gazing at the lamppost any longer."

    Markham silently followed Vance toward the park.

    Quaggy turned too and walked with us the short distance to the entrance of his apartment-hotel, where he took leave of us. At the great iron-grilled door he turned and said tauntingly: "Many thanks for not arresting me."

    "Oh, that's quite all right, Mr. Quaggy," Vance returned, halting momentarily and smiling. "The case isn't over yet, don't y' know. . . . Cheerio."

    At the corner Vance very deliberately lighted a cigarette and seated himself indolently on the wide stone balustrade extending along the east wall of the Nottingham Hotel.

    "I'm not bloodthirsty at all, Markham," he said, looking quizzically at the District Attorney; "but I rather wish the gentleman with the machine-gun had potted Mr. Fleel. And he was at such short range. I've never wielded a machine-gun myself, but I'm quite sure I could have done better than that. . . . And the poor Sergeant, dashing madly around at this hour. My heart goes out to him. The whole explanation of this evening's little contretemps lies elsewhere than with the mysterious green coupé."

    Markham was annoyed. He was standing at the curb, straining his eyes up the avenue to the north. "Sometimes, Vance," he said, without taking his eyes from the wide macadamized roadway, "you infuriate me with your babble. A lot of good it would have done us to have Fleel shot a few feet away from myself and the police."

    Vance joined Markham at the edge of the sidewalk and followed his intense gaze northward to the quiet blocks in the distance.

    "Lovely night," murmured Vance tantalizingly. "So quiet and lonely. But much too warm."

    "I'll warrant the Sergeant and McLaughlin overhaul that car somewhere." Markham was apparently following his own trend of thought.

    "Oh, I dare say," sighed Vance. "But I doubt if it will get us forrader. One can't send a green coupé to the electric chair. Silly notion—what?"

    There were several moments of silence, and then a taxicab came at a perilous rate out of the transverse in the park, swung south, and drew up directly in front of us.

    Simultaneously with the car's abrupt stop the door swung open, and Heath and McLaughlin stepped down.

    "We got the car all right," announced Heath triumphantly. "The same dirty-green coupé McLaughlin here saw outside the Kenting house Wednesday morning."

    The officer nodded his head enthusiastically.

    "It's the same, all right," he asserted. "I'd swear to it. Jeez, what a break!"

    "Where did you find it, Sergeant?" asked Markham. (Vance was unimpressed and was blowing smoke-rings playfully into the still summer air.)

    "Right up there in the transverse leading through the park." The Sergeant waved his arm with an impatient backward flourish, and barely missed striking McLaughlin who stood beside him. "It was half-way up on the curb. Abandoned. After the guys in it ditched the car they musta come out and hopped a taxicab up the street, because shortly after the green coupé turned into the transverse two guys walked out and, according to the driver here, took the cab in front of his."

    Without waiting for a reply from either Markham or Vance, Heath swung about and beckoned imperiously to the chauffeur of the cab from which he had just alighted. A short rotund man of perhaps thirty, with a flat cap and a duster too long for him, struggled out of the front seat and joined us.

    "Look here, you," bawled Heath, "do you know the name of the man who was running the cab ahead of you on the stand tonight who took the two guys what come out of the transverse?"

    "Sure I know him," returned the chauffeur. "He's a buddy of mine."

    "Know where he lives?"

    "Sure I know where he lives. Up on Kelly Street, in the Bronx. He's got a wife and three kids."

    "The hell with his family!" snapped Heath. "Get hold of that baby as soon as you can, and tell him to beat it down to the Homicide Bureau pronto. I wanta know where he took those two guys that came out of the transverse."

    "I can tell ya that right now, officer," came the chauffeur's respectful answer. "I was standin' talkin' to Abe when the fares came over from the park. I opened the door for 'em myself. An' they told Abe to drive like hell to the uptown station of the Lexington Avenue subway at 86th Street."

    "Ah!" It was Vance who spoke. "That's very interestin'. Uptown—eh, what?"

    "Anyway, I wanta see this buddy of yours," Heath went on to the chauffeur, ignoring Vance's interpolated comment. "Get me, fella?"

    "Sure I getcha, officer," the chauffeur returned subserviently. "Abe ought to be back on the stand in half an hour."

    "That's O.-K.," growled Heath, turning to Markham. "Gosh, Chief, I gotta get to a telephone quick and get the boys lookin' for these guys."

    "Why rush the matter, Sergeant?" Vance spoke casually. "We really ought not to keep Snitkin waiting too long at the apartment, don't y' know. I say, let's take this taxi and we'll be home in a few minutes. You can then use my phone to your heart's content. And this gentleman here"—indicating the chauffeur—"can return at once to his stand and await the arrival of his friend, Mr. Abraham."

    Heath hesitated, and Markham nodded after a quick look at Vance.

    "I think that will be the best course, Sergeant," the District Attorney said, and opened the door of the taxicab.

    We all got inside, leaving McLaughlin standing on the curb, and Heath gave Vance's address to the driver. As we pulled away, Heath put his head out of the window.

    "Report that empty car," he called out to McLaughlin. "And then keep your eye on it till the boys come up for it. Also watch for Abie till this fellow gets back—then get to the Kenting house and stand by with Guilfoyle."