Carroll's forehead was seamed with thought as he turned his car townward and sent it hurtling through the frosty air. He drove mechanically, scarcely knowing what he was doing.

He was frankly puzzled, enormously surprised and not a little startled. The afternoon had been at first amusing, then interesting—then utterly boring. Evelyn's chatter had put him in a state of mental coma—a lethargy from which he had been rudely aroused at sight of William Barker leaving the residence of Evelyn Rogers' sister.

There was something sinisterly significant in what he had seen. Not for a moment did he entertain the idea that Barker had been seeking employment. Negativing that possibility was the cold statement of the disinterested young girl that Barker had been there before, and, too, the fact that Barker was leaving from the front door instead of through the servant's door.

Obviously, then, Barker's mission had little to do with the matter of domestic employment. And now that he had stumbled upon something tangible—something definite—certain salient facts which had come to him through the haze of girlish chatter began to stand out and assume proper significance.

For instance there was her constant repetition of the fact that Roland Warren had been a frequent visitor at the Lawrence home. That might mean nothing: it might mean a great deal. Certainly it was indicative of a close friendship between the dead man and the members of that household. He paid little heed to the girl's protestations that Warren had been in love with her. No expert in the ways of the rising generation, Carroll yet knew that no man of Warren's maturity had unleashed his affections on a girl who yet lacked several years of womanhood. The dead man had been too much of an epicure in femininity for such as that.

But Carroll knew that in that house there was another woman: Naomi Lawrence—Evelyn's sister. And while Evelyn had dismissed the sister with a few words, Carroll remembered that the girl had described her as being "not so bad looking" and had also said that Mrs. Lawrence fancied that when Warren called at the house, he was calling on her.

There, too, was the matter of Gerald Lawrence to be considered. Evelyn insisted that Gerald was "an old crab" and also that he was of an exceedingly jealous disposition. If that were true, then his jealousy, coupled with a possible intimacy between Mrs. Lawrence and Warren might have been ample motive for the taxicab tragedy.

It was all rather puzzling. Carroll's mind leaped nimbly from one mental trail to another. He held himself in check, afraid that his deductions were proceeding too swiftly. He was acutely conscious of the danger of jumping too avidly on this single tangible clue which had come to him after four days of fruitless search. There was danger, and he knew it, of attaching untoward importance to a combination of circumstances which under other conditions might not have excited him in the slightest degree.

It was there that the case bewildered him—and he was not slow in confessing his bewilderment. Up to this moment there had been an appalling dearth of physical clues—of things upon which a line of investigation could be intelligently based. And he knew that now something had turned up, he must watch himself lest the circumstance assume unreasonable and unwarranted proportions.

The somber outline of police headquarters bulked in the night. Carroll swung down the alley, shut off his motor and entered. He found Leverage in his office and settled at once to a discussion of developments. But when he would have spoken Leverage cut him off. Leverage had news—and Leverage was frankly proud of the fact that he had news.

"Just got an interesting report from Cartwright," he announced.

"Regarding Barker?" Carroll hitched his chair forward eagerly.

"Yes."

"What is it?"

"Yesterday afternoon at five o'clock William Barker went to the residence of Mr. and Mrs. Gerald Lawrence. He was in the house eighteen minutes."

"Why wasn't this told me last night?"

"Cartwright didn't think anything of it. He included it in his report which was turned in to me this morning."

"Why did he think it was unimportant?"

"Said he thought Barker was probably looking for a job."

"And he doesn't think so now?"

"No-o. That is: he thinks circumstances make an investigation worth while. You see, just a few minutes ago Barker went to the Lawrence home again. This time he was there four minutes."

"Does Cartwright know who was at home at that time?"

"He thinks so. He says a maid let Barker in and that apparently Mrs. Lawrence let him out. A young girl—whom Cartwright believes to be Mrs. Lawrence's sister—drove up just as Barker was leaving. She was in the car with some man—but he didn't get out. Then, just a minute ago, Gerald Lawrence reached home. So the idea is that Mrs. Lawrence was alone with the servants when Barker called."

"And yet he only remained four minutes?"

"That's what Cartwright 'phoned." Leverage paused. "What do you make of it, Carroll?"

"Off-hand," answered the youthful-appearing detective, "I'd say that
Barker had called to see Mr. Lawrence."

"Why?"

"We'll suppose Lawrence was home on the occasion of Barker's first visit—do you know whether he was?"

"No. I asked. Cartwright doesn't know. Couldn't stay, you know—because he was under orders to follow Barker. Tonight he sent Reed after Barker and he watched the Lawrence house."

"Good. If it is so that Lawrence was at home when Barker called yesterday evening and Barker then remained eighteen minutes; whereas this afternoon, when we know that no one but Mrs. Lawrence was there—and he remained but four minutes—it is fairly reasonable to suppose that he was calling to see Mr. Lawrence."

"I think you're right, Carroll."

"I'm not at all convinced about that. But if we're proceeding along lines of pure logic, that is the answer."

"How about the man who drove up with the kid sister?"

Carroll smiled. "I'm sure he had nothing whatever to do with the murder."

"Good Lord! I didn't think he had. But still he may have been a friend, and—"

"That man was all right. I know that."

"You know?" Leverage was incredulous.

"Yes." Carroll grinned. "I was the man!"

"You—? Holy sufferin' mackerel! Sa-a-ay! Was that chicken I seen you with downtown, Lawrence's sister-in-law?"

"Yes. Miss Evelyn Rogers. And Good Lord! Leverage, how that girl can talk! She holds all records for conversational distance and speed. She talked me dumb."

Leverage was staring respectfully at Carroll. "If you were the man who was with her, David—you must have seen Barker when he left the house."

"I did."

The face of the chief showed his disappointment: "That's what I get for thinking I had a real surprise up my sleeve. You sit back with that innocent kid face of yours and let me spill all the dope—and then tell me perfectly matter-of-factly that you knew it all the time. How'd you ever get wise to the thing, anyway?"

Carroll was honest. "No thanks to my sagacity, Leverage. One of those pieces of bull luck which I have always contended play an enormous part in solving crime. In the first place Evelyn Rogers came to me the day after Warren was killed to assure me that Miss Gresham had a perfect alibi. This afternoon she lassoed me and dragged me into an ice cream place because she wanted to prove to some of her school companions that we were really friends." Carroll chuckled. "I quaffed freely from the fountain of youth—and enjoyed it awhile. Then I got bored stiff. Took her to the movies—she invited me—and did it only because I've passed beyond the years of adolescence and didn't know how to crawfish out of it. After which—because it seemed the proper thing to do—I volunteered to ride her home in my car. And it was then that I saw Barker leaving the Lawrence home. So you see, Leverage, my knowledge is the result of pure accident—and not at all the fruit of keen perception."

"Well, anyway—Carroll: you knew! And that takes the edge off what I told you."

"Not at all," returned Carroll seriously. "For while what I discovered is perhaps valuable—that combined with the fact that Barker has been there once before: and that on his first visit when Lawrence was probably at home he stayed nearly five times as long as he did when we know that Lawrence was not there—that is of help—or ought to be."

"What do you think of it?"

Carroll hesitated. "I don't know what to think, Eric. I'm afraid I'm thinking about it more than I have any right. We've been so long without anything to work on, that we're liable to let this bit of information throw us off our balance. But of course we'll look more deeply into it."

"How?"

Again Carroll chuckled. "Our little friend, Miss Rogers, is suffering from a large case of hero-worship. I'm it! And so—when I saw Barker leaving her home—I immediately made an engagement to call upon her to-morrow night!"

"You call on that kid—" Suddenly Leverage lay back in his swivel chair and gave vent to a peal of raucous laughter. He banged his fist on the arm of the chair: "Oh! Boy! That's the snappiest yet. David Carroll paying a social call on a seventeen-year-old kid! Mama! Ain't that the richest—"

Carroll made a wry face. "Needn't rub it in. It's bad enough anyway. And"—growing serious—"I'm hoping to meet Mr. and Mrs. Lawrence. They ought to prove interesting."

But Leverage could not tear himself away from the sheer humor of the situation: "What the devil you and her going to talk about? Foxtrot steps? Is the camel walk vulgar? Frat dance? Next week's basketball game? Sa-a-ay! David—I'd give my chances of Heaven to be hidden behind the door."

"So would I," said Carroll wryly.

"Above all things," counseled Leverage with mock severity: "Don't you go making love to her."

Carroll reached a muscular hand across the table. His sinewy fingers closed around a glass paperweight. He held this poised steadily. "One more crack out of you, Eric, and I'll slam this against your head. You're a pretty good chief of police—but you're a rotten humorist."

"Just the same," grinned the chief, "I can see that this joke is on you!
And now—what?"

"For one thing," and Carroll's manner was all business again, "I want every bit of dope I can get on Gerald Lawrence and his wife. I know that Warren was very intimate at the house: friendly with both wife and husband, according to what Miss Rogers says. That connects them up. What I want to find out now is where both of 'em were the night Warren was killed. Put a couple of your best men out to gather this dope—there isn't any of it too minor to interest me. Meanwhile, I'll pump the kid. I have a hunch that this isn't going to be a cold trail."

"It better not be—or Mr. David Carroll is going to find himself with one unsolved case on his hands. Yes, sir—if this is a blind lead, we're up against it for fair."

"It isn't going to be entirely blind," postulated Carroll. "Barker assures us of that!"