Free ARM by Larry Niven Page A

up bloodstains. White outlines to mark the vanished body, the generator, the poker.
    Something knocked at the back door of my mind. I looked from the chalk outlines, to the open elevator, to the chalk ... and a third of the puzzle fell into place.
    So simple. We were looking for K 1 ... and I had a pretty good idea who he was.
    Ordaz was asking me, “How did you happen to arrive with Mr. Porter?”
    “He came to my office. We were talking about a hypothetical killer—” I lowered my voice slightly. “—a killer who isn't Janice.”
    “Very good. Did you reason out how he must have left?”
    “Not yet. But play the game with me. Say there was a way.”
    Porter and Janice joined us, their arms about each other's waists. Ordaz said, “Very well. We assume there was a way out. Did he improvise it? And why did he not use the elevator?”
    “He must have had it in mind when he got here. He didn't use the elevator because he was planning to take the machine. It wouldn't have fit.”
    They all stared at the chalk outline of the generator. So simple. Porter said, “Yah! Then he used it anyway and left you a locked room mystery!”
    “That may have been his mistake,” Ordaz said grimly. “When we know his escape route, we may find that only one man could have used it. But of course we do not even know that the route exists.”
    I changed the subject. “Have you got everyone on the elevator tape identified?”
    Valpredo dug out his spiral notebook and flipped to the jotted names of the people permitted to use Sinclair's elevator. He showed it to Porter. “Have you seen this?”
    Porter studied it. “No, but I can guess what it is. Let's see ... Hans Drucker was Janice's lover before I came along. We still see him. In fact, he was at that beach party last night at the Randalls'.”
    “He flopped on the Randalls’ rug last night,” Valpredo said. “Him and four others. One of the better alibis.”
    “Oh, Hans wouldn't have anything to do with this!” Janice exclaimed. The idea horrified her.
    Porter was still looking at the list. “You know about most of these people already. Bertha Hall and Muriel Sandusky were lady friends of Uncle Ray's. Bertha goes backpacking with him.”
    “We interviewed them, too,” Valpredo told me. “You can hear the tapes if you like.”
    “No, just give me the gist. I already know who the killer is.”
    Ordaz raised his eyebrows at that, and Janice said, “Oh, good! Who?” which question I answered with a secretive smile. Nobody actually called me a liar.
    Valpredo said, “Muriel Sandusky's been living in England for almost a year. Married. Hasn't seen Sinclair in years. Big, beautiful redhead.”
    “She had a crush on Uncle Ray once,” Janice said. “And vice versa. I think his lasted longer.”
    “Bertha Hall is something else again,” Valpredo continued. “Sinclair's age and in good shape. Wiry. She says that when Sinclair was on the home stretch on a project, he gave up everything: friends, social life, exercise. Afterward he'd call Bertha and go backpacking with her to catch up with himself. He called her two nights ago and set a date for next Monday.”
    I said, “Alibi?”
    “Nope.”
    “Really!” Janice said indignantly. “Why, we've known Bertha since I was that high! If you know who killed Uncle Ray, why don't you just say so?”
    “Out of this list, I sure do, given certain assumptions. But I don't know how he got out, or how he expected to, or whether we can prove it on him. I can't accuse anyone now . It's a damn shame he didn't lose his arm reaching for that poker.”
    Porter looked frustrated. So did Janice.
    “You would not want to face a lawsuit,” Ordaz suggested delicately. “What of Sinclair's machine?”
    “It's an inertialess drive, sort of. Lower the inertia, time speeds up. Bera's already learned a lot about it, but it'll be a while before he can really...”
    “You were saying?” Ordaz asked when I trailed off.
    “Sinclair was finished