In Karen: A Brother Remembers (Harper Select, out now), actor Kelsey Grammer recalls the vibrancy of his younger sister's life, as well as the horrific circumstances of her murder in 1975, when she was almost 19.

In the book, you tell the story of Karen's life. What would you like readers to most know about her?

That she was lightning in a bottle. She was a wonderful, loving, fantastic person—a very brave person. She faced life, and drank it with all the gusto that a person can. She suffered the same tragedies I did as a young person [the Grammer siblings' father was also murdered], and maybe she even suffered more. But she never gave up on life. She really fought for life—even down to her last moments, she was still fighting to live.

You wrote a previous memoir that referenced the numerous losses of family members in your life. At what point did you decide to write a book that was just about Karen's life and death?

It was only about three years ago, when I was instructed by Esther, a medium, that Karen wanted me to do so. So, I had a mission to tell her story, which was intertwined with my own. There were things where I'd start going down one alleyway and think to myself, Oh, that's not really about Karen, and so I'd pull back and redirect. I made an effort to provide some humor, because I wanted the book to be, as odd as that may sound in the context of writing about something so tragic, fun as well. We had so much fun in our early years. We were having fun as young people, discovering life, and discovering love. We did it together, and she was the best person I knew—she was the true love of my life at that time.

Did the finished book differ from how you'd originally thought about it?

Yes, it's funny. Initially, I wrote the first eight pages, where I was just writing down notes after I'd sort of absorbed the idea that I was going to try to tell Karen's story. And then, it started to look more like a paragraph, and then it started to look more like pages in a book. And I suddenly realized, I'm going to write a book about Karen. And I just surrendered to the idea that I was going to put myself back to remembering our life together, and to take the journey and have it surprise me. So many realizations came up. Once the door was open, memory became almost transparently accurate. It did not have a time signature on it anymore. It just had a flow. So, I surrendered to this idea that I would be doing stream of consciousness, which was never one of my favorite styles.

Why not?

When I read A Portrait of the Artist as a Young Man, and its beginning with stream of consciousness, I thought, This is a load of crap. But Mr. Joyce, aside, I wanted the reader to understand that I know that they're reading the book, and I know that I'm writing it. At the same time, we're all doing this together and that it's a shared experience. I remembered that Henry Fielding kept telling people, when he was writing Tom Jones, that it was the best book they were ever going to read. I didn't quite come out with that.

At a certain point you decided to include some very, very graphic and painful details about your sister's last hours, which are really searing to read. What led you to decide to go into those details?

I was conflicted about quoting from the actual police report. I did think it was important that, in terms of context, readers understood how awful her last day was. But I also wanted anybody else who has been through the same kind of unimaginable thing to understand that I was writing, from experience, to the ones that I was hoping to console because I had an opportunity to talk about, How do you live with it? How do you go on? To have those people aligned with my experience, they needed to know what it was, what Karen's was.

In this book, you wrote that you felt guilty for not protecting Karen, even though you were nowhere near where she was murdered at the time. Have you absolved yourself of that guilt?

Mostly. I'm certainly closer. It does creep up once in a while, but it's a lot better. I'm definitely lighter as a result of writing the book.