I need help with an Identification.

[Vistropiate]

Hello everyone. I write this in the midst of grief and sadness, because in my backyard today was what we thought was a rattlesnake. Having previously encountered a rattlesnake that had nearly killed one of my cats the day before, my parents panicked and unfortunately killed the snake.

It wasn't a rattlesnake, and I can't tell what it is.

I'd like to know what you guys think it is. I live in Southern California, San Diego. It's been generally hot the past couple of days. Closest I could find was a California Kingsnake, but I just wanted to check what you guys thought.

Image is attached of the snake's head and most of it's body, and I have one of it's tail end if needed.

Again, I am truly regretful that I let panic take place of where curiosity and caution should've taken place. I feel truly horrible for letting the beautiful snake die, and any closure would be greatly appreciated.