If you admit that she's never coming home, it's like you're admitting defeat.

Or that she's dead.

A hard-working wife, a loving mother, a woman with a complicated love life.

She was having affairs. They worked in the same office areas.

They spent some time after hours together.

Kathy was trying to break off the relationship.

Now, the secret was out, replaced by a mystery.

She never returned from lunch.

We did consider that her husband may have known that his wife was having an affair.

Where was she?

There were just no answers.

Nearly 30 years, 60 investigators, and it all kept coming back to one elusive suspect.

He just very calmly said, I know how to get rid of a body so it would never ever be found.

To him, I think murder is something that can be done over lunch hour.

You were just a heartbeat away from not having a case.

It was basically an hour or never situation.

They couldn't prove it then. Could they prove it now?

I'm Lester Holt, and this is Dateline.

Here's Josh Mankowitz with, she didn't come home.

Time can be like a river, a long stream of events rushing by.

Most barely make a ripple, but a few, like the sudden loss of a close friend, a child, or a parent.

Have a way of circling back upon us in a ceaseless loop of memory and regret.

...