“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.”