“Then you think Kato—­”

“Not too fast,” cautioned Craig.  “Remember, others had access to the kitchen, too.”

In spite of his hesitancy, I could think only of the two paragraphs we had read in Mrs. Wardlaw’s will, and especially of the last.  Might not Kato have been forced or enticed into a scheme that promised a safe return and practically no chance of discovery?  What gruesome mystery had been unveiled by the anonymous letter which had first excited our curiosity?

It was late in the afternoon that Commissioner Leslie called us up, much excited, to inform us that the drooping pigeon was already pecking at food and beginning to show some interest in life.  Kennedy seemed greatly gratified as he hung up the receiver.

“Almost dinner-time,” he commented, with a glance at his watch.  “I think we’ll make another hurried visit to the Wardlaw apartment.”

We had no trouble getting in, although as outsiders we were more tolerated than welcome.  Our excuse was that Kennedy had some more questions which we wished to ask Miss Langdale.

While we waited for her we sat, not in the study, but in the parlor.  The folding-doors into the dining-room were closed, but across the hall we could tell by the sound when Kato was in the kitchen and when he crossed the hall.

Once I heard him in the dining-room.  Before I knew it Kennedy had hastily tiptoed across the hall and into the kitchen.  He was gone only a couple of minutes, but it was long enough to place in the food that was being prepared, and in some unprepared, either the tablets he had made or a powder he had derived from them crushed up.  When he returned I saw from his manner that the real purpose of the visit had been accomplished, although when Miss Langdale appeared he went through the form of questioning her, mostly on Mrs. Marbury’s sickness and death.  He did not learn anything that appeared to be important, but at least he covered up the reason for his visit.  Outside the apartment, Kennedy paused a moment.  “There’s nothing to do now but await developments,” he meditated.  “Meanwhile, there is no use for us to double up our time together.  I have decided to watch Kato to-night.  Suppose you shadow Doctor Aitken.  Perhaps we may get a line on something that way.”

The plan seemed admirable to me.  In fact, I had been longing for some action of the sort all the afternoon, while Kennedy had been engaged in the studies which he evidently deemed more important.

Accordingly, after dinner, we separated, Kennedy going back to the Forum Apartments to wait until Kato left for the night, while I walked farther up the Drive to the address given in the directory as that of Doctor Aitken.

It happened to be the time when the doctor had his office hours for patients, so that I was sure at least that he was at home when I took my station just down the street, carefully scrutinizing every one who entered and left his house.