For lovely Robin, the late shift was her last.

She was laying face down, a pool of blood under one side.

Just one tiny clue.

A piece of curved foam rubber.

There was a suspect, but he had an alibi, until this revelation.

I said I have something that you need to know.

Thanks for joining us, I'm Lester Holt.

Sometimes it takes a special eye to look at a crime scene, and spot the thing that's out of place.

The clue that will crack the case, in this story that thing was so inconsequential looking,

no one even knew what it was, let alone what it meant.

It took almost two decades, a team of determined investigators, and a detective with an unusual background to find out.

Here's Keith Morrison.

It was the night before Halloween, October 30th late midnight approaching.

It happened in one of the middle-class suburbs that sprawl across the Los Angeles Basin.

Inside a fast food franchise, closed for the night, a frantic scrabbling, running feet, then silence.

The next morning, not far away, the Hoynes family daughters prepared for a favorite celebration.

Kim was the eldest, then Robin, Trisha, and Wendy.

Excited because this was Halloween, one of the best days of the year.

Oh, loved it. We'd trick a treat, and then we'd sort the candy, and we'd be trading what we liked.

A Halloween morning long ago, it was 1984.

The morning after the incident in the fast food place, it started warm and sunny, that bubble of innocence, before anyone knew a thing.

Wendy donned her Halloween costume, wore it to school, as Trisha, who wore hers to work.

...