Charlie Fuller was seated in my chair at the table, staring at the wall. A tiny stream of blood was running down his forehead and into one eye. He was dead

It took me some moments to comprehend the fact of his death, and even after I had located the bullet wound just above his hairline, I still could not accept the reality of it. My first thought had been suicide, but then I saw this was impossible. The bullet had obviously killed him instantly, and there was no gun any­where in sight — in fact. Fuller's rifle was missing from its usual place in the corner near the door.

But if not suicide, what?

There was no other explanation. Somehow he had killed himself. I switched on the radio and sent a message to the effect, telling them I'd bring in the body by snowmobile as soon as I could.

Then, as I was starting to pack my things, I remembered the coffee. Do men about to commit suicide start making breakfast? Do they put a pot of coffee on the stove?

And then I had to face it. Charlie Fuller had not killed himself. It seemed impossible — but there it was. I sat down opposite the body, then got up to cover it with a blanket, and then sat down again.

What were all the possibilities? Suicide, accident, murder — as simple as that. Not suicide. Not accident. He certainly hadn't been cleaning his gun at the time.

That left only one possibility.

Murder.

I walked over and crouched behind his chair, trying to see what he must have been seeing in that final moment.

And then I saw it. Directly opposite, in the center of a frosted window, there was a tiny hole. I hadn't noticed it before — the frost had effectively camouflaged the hole. A few cracks ran from it, but the snow had somehow kept the window from shattering completely.

The bullet had come from outside — the mystery was solved!

But as soon as I put on my coat and went outdoors, I realized that a greater mystery had taken its place. Though the drifting snow had left a narrow walkway under the roof of the cabin, drifts higher than my head surrouned us on all sides. No one could have approached the cabin through that snow without leaving a visible trail.

I made my way to the window and saw the butt of Fuller's rifle protruding from the snow. I pulled it out and stared at it, wondering what it could tell me. It had been recently fired, it was the murder weapon, but there was nothing more it could say.

I took it back into the cabin and sat down. Just the two of us, no one else, and somebody had murdered Charlie Fuller.

As the day passed into noon, I knew I would have to be moving soon. But could I go back under the circumstances? Charlie Fuller was dead, and I had to discover how it had happened.

Pacing the cabin, I knew that the answer must lurk here somewhere, within the walls of our temporary home. I went back in my mind over our conversations about Grace. He had loved her, he had wanted her — of that much I was certain. Could he have committed suicide in such a manner that 1 would be accused of his murder?

No, there were two things against that theory — it wouldn't get him Grace, and it wouldn't get me convicted of the crime. Because even now I could change the scene any way I wanted, invent any story I liked. The police would never even make the trip to the cabin to check my story. I had already called it suicide in my radio report, but I could change it to accident. And there was no one to call it murder.

No one but myself.

I went outside again and started sifting through the snow where I'd found the rifle. But there was nothing — a few bits of icicle, but nothing more. Here and there Fuller's footprints remained undrifted, from his icicle-breaking expedition, but I could identify no other prints. If someone had stood at that window to kill Charlie Fuller -...

But no one could have! The snow and crystallized frost had made the window completely opaque. Even if an invisible murderer had dropped from the sky, and somehow got Charlie's rifle out of the cabin, he could not have fired at Charlie through that window because he could not have seen him through it!

So I went back inside to the rifle, emptied it, and tried the trigger. It had been adjusted to a hair trigger — the slightest pressure of my finger was enough to click the hammer on the empty chamber.

Suddenly I felt that I almost had an answer. I stood staring at the blanket-covered figure in the chair, then went outside and looked through the bullet hole at it again. Lined up perfectly, even through an opaque window.

And then I knew who had murdered Charlie Fuller.

I was staring at his body in the chair, but it was my chair! Twenty minutes later, and I would have been sitting in that very chair, eating breakfast. Charlie would have called me when the coffee was ready, and I would have come out to sit in that chair, as I did every morning.

And Charlie Fuller would have killed me.

It took me five minutes of sorting through the bits of icicle in the snow under the window to find the one that was something more. It was ice, but ice encased in a tiny heat-sealed plastic pouch. We used pouches of all sizes in the lab for the rock speci­mens we collected. This one had served a different purpose.

Charlie had driven one of the icicles into the snow and balanced the rifle on top of it — probably freezing it to the icicle with a few drops of water. Then he had wiped away a tiny speck of frost on the window to line the gun barrel with the chair in which I would be sitting. He'd fixed the rifle with a hair trigger, and then jammed the tiny plastic pouch of water between the front of the trigger and the guard.

When the water in the pouch froze, the ice expanded against the trigger, and the rifle fired through the window at the chair. The recoil had thrown the rifle free of its icicle support, and the frozen pouch of water had dropped into the snow like a simple piece of ice.

And what had gone wrong? Charlie Fuller must have timed the freezing of the water filled pouch, but he probably hadn't timed it in subzero cold with a wind blowing. The water had simply frozen sooner than he'd planned — while he was sitting in my chair for a moment, adjusting it to the precise position facing the window.

But why had he gone to all that trouble to kill me, when we were alone? I thought about that all the way back to Caribou in the snowmobile. He'd probably feared that it would be like the animals he'd told me about, that at the final moment he wouldn't have been able to squeeze the trigger. Perhaps in the night he'd even stood over my bed with his rifle, unable to go through with it. This way had made it impersonal, like a lab experiment to be set up and observed.

So Charlie Fuller had murdered himself. But for the authorities, and for Grace, I decided to stick to the suicide story. I didn't think they'd bother too much about things like the absence of powder burns. Under the circumstances, they were stuck with my story, and I wanted to keep it simple. As I said in the beginning, I'm no detective.