It is small consolation, I know, Mrs. Welsh, but I have never forgotten your daughter.

In the two decades since we found her lifeless body face down on her couch, I have thought of Kathleen every year on December 12. I lived in a two-room apartment in the narrow brick building on Beacon Hill where Kathleen was murdered 20 years ago.

It was my sister's 30th birthday.

I left my third-floor walkup that Sunday afternoon for the family party in North Cambridge, stopping briefly outside Kathleen's closed door on the first floor. I had forgotten my boots and considered going back upstairs.

I knew I'd catch hell from my mother for not dressing for the weather. But I was late, so I stepped into the damp street in a pair of patent leather pumps, my birthday gift of Jean Nate bath powder and cologne tucked under my arm.

It was dark and the streets were slick by the time I headed home. My walk up Revere Street from the Charles Street T station was more like a slide. I kept my head down, scanning the brick sidewalks for the icy patch that my mother warned would send me flying in my impractical shoes.

Police think Kathleen's killer might have been fleeing as I was inching my way up the hill. Had someone passed me? Did I see anyone leaving the building? Running up or down the hill?

I am still saddened to say, Mrs. Welsh, that I saw only my shoes, the bricks and the front doorstep of our apartment house where I did slip, at last. I fell against the heavy front door. It gave way against my shoulder, sending me stumbling into the hall.

How many times had we complained about that unreliable lock?

The half-dozen apartments in the building were all occupied by women in their 20s, living alone. We knew that security in the building was not what it should be, that safety on the back side of Beacon Hill was uncertain. But we wanted to be downtown, close to the schools we attended or the entry-level jobs we held, so we paid too much for apartments that were too small and alternately too hot or too cold.

We'd pass one another in the entry, exchanging the casual greetings of young strangers living parallel lives. We knew Kathleen was a graduate music student at Boston University, working part-time at the Lenox Hotel. I was a secretary at The Boston Globe, working overtime to prove I could do more.

Kathleen stood out among our serendipitous sorority because of her dogs, the two sleek Dalmatians who shared her apartment. She taught us to approach slowly if we wanted to pet them, to be careful not to startle them, lest they snap. We felt safer having them in the building.

Later, we would wonder why her dogs, always so protective, had not repelled Kathleen's killer.

That evening, as I steadied myself against the wobbling hall banister, I saw that Kathleen's apartment door was wide open. My eyes took in the flickering television screen, the Christmas presents on the table, the roll of wrapping paper. I heard the low growl of the dogs.

How, detectives later would ask, could I have registered the color of the gift wrap -- red with green designs -- and not seen the blood splattered on the wall?

I still have no answer, beyond the tricks a mind must play when it sees a sight too horrific to absorb. I did stop at the second-floor landing, though, to ask a neighbor if it didn't seem odd, Kathleen's door being open like that.

The neighbor -- her name is lost to time -- sold Avon cosmetics. She had an order for Kathleen. She'd just bring it down and make sure everything was all right.

The rest is surreal. The scream. Kathleen on the couch. The dogs guarding her body. The call to police. The sirens and blue lights. The hall full of blue uniforms. The detective ordering us to wait in our separate apartments. The silence shattered by two terrifying gunshots. Was the murderer still in the building?

The grief we felt for Kathleen and the rage we felt at her killer was redirected toward police when we realized they had shot and killed her dogs. Better to ask "why?" of them than to ask why someone stabbed my downstairs neighbor 56 times while I made my way home from my sister's birthday party.

I moved away from Revere Street as soon as I could, Mrs. Welsh, but I never forgot your daughter or the dogs she loved. Twenty years after that terrible night, I still pick up this newspaper every day hoping to read that the police have caught Kathleen's killer.