For a long time, I fancied my ability to observe and draw conclusions was one of my most stellar qualities. It made me a modern Sherlock Holmes, a cataloguer of human nature. Or so I thought. But what about the effect of the observer on the observed? I see myself  somewhat differently now. I'll explain.

Last Tuesday morning I encountered an interesting specimen on the bus, someone I hadn't seen before and haven't seen since: the lady with the hair. It was long, white-blonde hair -- obviously a dye job -- and she was combing it. I could tell she cared about her appearance, cared a little too much. She must have been about 50, but she wore a miniskirt and a black leather jacket, the outfit of a much younger woman, though she was slim enough to pull it off without looking too ridiculous. Her face was handsome (it might have been pretty ten years ago) and pale and blurred from too much make-up. The lips were glossy and pink, matching the nails on the hand that clutched the tortoise-shell comb, the teeth of which glided through that long, silver-white hair.

As she combed, she looked about the bus and through the windows, never quite focusing on anything or  anyone. I noticed that she looked around in all directions except mine. She must know I'm watching her,  I thought. And I bet she's enjoying it. I know just what she needs . . . 

She kept combing, first one side of her head, then the other, then the back, then the bangs, then the side again. I wondered how long she could keep it up and began to time her with my watch. I counted five minutes of non-stop combing, and still she didn't stop. Oh, yes, that's mental, I thought. Something's not right.

I'm not exactly not vain myself. I'm 30, lean, not bad. On the trip home, I check my reflection in the bus's darkened window and smooth my hair with my fingers. Society gives women far more latitude, I think, to primp in public. But this was absurd.

The bus was dropping off more and more passengers at each stop, and soon the lady with the hair and I were the only ones sitting on the long seats up front.

My office is near the end of the line, and I wondered which of us would get off first. I figured she'd put the comb away as we drew near her stop. But the combing went on and on.

After a while, she paused for a moment and opened her purse. OK, I thought, she's getting off soon. But no. She pulled out a small mirror, stared into it, and resumed her combing. I suppressed a strong desire to giggle. What an obsession, I thought. With all that manipulation, I'm surprised she still has a hair on her head.

Then she did something far weirder. She put the little mirror away, stood up, grabbed the handrail to steady herself as the bus swayed, and began to move to the driver's area. She stooped slightly, looked into the rear-view mirror over the driver's head and began to comb again. I wondered if she was actually looking at me in the mirror, trying to evaluate this curious man watching her so intently.

"Hey, you mind?" the driver said. She didn't reply, but began to move back to her seat, a bit unsteady on her high heels as the bus turned a corner. Her head was tilted back a bit and she was smiling slightly. She looked at me for a fraction of a second before sitting down, slowly and regally. Then she resumed her combing and glancing around.

We were drawing close to Cole Plaza, where I work in the Police Building -- in the Video Analysis Lab. I stood up as the bus pulled to my stop, with a twinge of regret that I wouldn't be able to see this lady get off -- just to see if the combing would cease at that point. But she stood up, too.

I stepped off first, without looking back. If she was following me, I didn't want to encourage her. She was surely some kind of lunatic, and I didn't want any trouble.

I passed through the revolving door of the Police Building. The exterior walls of the lobby are plate glass, and as I waited for the elevator, I couldn't help looking over my shoulder. There she was, standing out on the plaza by the roaring fountain. She was staring at me and, of course, combing that long, platinum hair, now phosphorescent in the sunlight.

She smiled, but I turned away. And at that moment, I realized that I'm not really a detective at all. Just a voyeur. And a cold, cold bastard.

I got into the elevator and, just as the doors closed, looked back at her again. The combing had stopped at last. She was still looking at me, but no longer smiling, and she was touching her eyes.