9.00 a. m. Arnesson left house to go to university library.
9.15 a. m. Belle Dillard left house for the tennis courts.
9.30 a. m. Drukker called at house to see Arnesson.
9.50 a. m. Drukker went down-stairs to archery-room.
10.00 a. m. Robin and Sperling called at house and remained in drawing-room for half an hour.
10.30 a. m. Robin and Sperling went down to archery-room.
10.32 a. m. Drukker says he went out for a walk, by the wall gate.
10.35 a. m. Beedle went marketing.
10.55 a. m. Drukker says he returned to his own house.
11.15 a. m. Sperling went away by wall gate.
11.30 a. m. Drukker says he heard a scream in his mother’s room.
11.35 a. m. Professor Dillard went on balcony of Arnesson’s room.
11.40 a. m. Professor Dillard saw Robin’s body on archery range.
11.45 a. m. Professor Dillard telephoned to District Attorney’s office.
12.25 p. m. Belle Dillard returned from tennis.
12.30 p. m. Police arrived at Dillard house.
12.35 p. m. Beedle returned from market.
2.00 p. m. Arnesson returned from university.
Ergo: Robin was killed at some time between 11.15 (when Sperling departed) and 11.40 (when Professor Dillard discovered body).
The only other persons known to have been in the house during this time were Pyne and Professor Dillard.
The disposition of all other persons connected in any way with the murder was as follows (according to statements and evidence now in hand):
1. Arnesson was at the university library between 9 a. m. and 2 p. m.
2. Belle Dillard was at the tennis courts between 9.15 a. m. and 12.25 p. m.
3. Drukker was walking in the park between 10.32 a. m. and 10.55 a. m.; and was in his study from 10.55 a. m. on.
4. Pardee was in his house the entire morning.
5. Mrs. Drukker was in her room the entire morning.
6. Beedle was marketing between 10.35 a. m. and 12.35 p. m.
7. Sperling was on his way to the Grand Central Station between 11.15 a. m. and 11.40 a. m., at which hour he took a train for Scarsdale.
Conclusion: Unless at least one of these seven alibis is shaken, the whole weight of suspicion, and indeed the actual culpability, must rest upon either Pyne or Professor Dillard.
When Markham finished reading the paper, he made a gesture of exasperation.
“Your entire implication is preposterous,” he said irritably; “and your conclusion is a non-sequitur. The chronology helps set the time of Robin’s death, but your assumption that one of the persons we’ve seen to-day is necessarily guilty is arrant nonsense. You completely ignore the possibility that any outsider could have committed the crime. There were three ways of reaching the range and the archery-room without entering the house—the wall gate on 75th Street, the other wall gate on 76th Street, and the alleyway between the two apartment houses, leading to Riverside Drive.”
“Oh, it’s highly probable that one of these three entrances was used,” returned Vance. “But don’t overlook the fact that the most secluded, and therefore the most likely, of these three means of entry—to wit, the alleyway—is guarded by a locked door to which no one would be apt to have a key except some member of the Dillard household. I can’t picture a murderer walking into the range from either of the street gates: he would be taking too many chances of being seen.”
Vance leaned forward seriously.
“And, Markham, there are other reasons why we may eliminate strangers or casual prowlers. The person who sent Robin to his Maker must have been privy to the exact state of affairs in the Dillard house this morning between a quarter past eleven and twenty minutes to twelve. He knew that Pyne and the old professor were alone there. He knew that Belle Dillard was not roaming about the premises. He knew that Beedle was away and could neither hear him nor surprise him. He knew that Robin—his victim—was there, and that Sperling had departed. Moreover, he knew something of the lie of the land—the situation of the archery-room, for instance; for it’s only too plain that Robin was killed in that room. No one who wasn’t familiar with all these details would have dared enter the grounds and staged a spectacular murder. I tell you, Markham, it was some one very close to the Dillard ménage—some one who was able to find out just what conditions obtained in that household this morning.”
“What about that scream of Mrs. Drukker’s?”
“Ah, what about it, indeed? Mrs. Drukker’s window may have been a factor that the murderer overlooked. Or perhaps he knew about it and decided to take that one chance of being seen. On the other hand, we don’t know whether the lady screamed or not. She says No; Drukker says Yes. They both have an ulterior motive for what they poured into our trustin’ ears. Drukker may have told of the scream by way of proving he was at home between eleven and twelve; and Mrs. Drukker may have denied it for fear he wasn’t home. It’s very much of an olla podrida. But it doesn’t matter. The main point I’m trying to make is that only an intimate of the Dillard house could have done this devilish business.”
“We have too few facts to warrant that conclusion,” asserted Markham. “Chance may have played a part——”
“Oh, I say, old man! Chance may work out to a few permutations, but not to twenty.—And there is that note left in the mail-box. The murderer even knew Robin’s middle name.”