Up next, an execution-style murder and a sophisticated cover-up.

It was obvious right from the start that this crime scene had been altered.

An eyewitness sees two men leaving the scene, but how much did he really see?

We were scratching our heads for a little bit.

Someone held a grudge against the family.

Maybe he was angry enough to come back on her bed on Brian.

She was definitely scared of this guy.

But was that enough to lead to murder?

Eight months after getting married, Brian and Beverly Mock moved into their dream home in rural Washington State.

She loved him so much. He loved her so much, too. I mean, it showed in their eyes.

30-year-old Brian worked for an air conditioning company.

Beverly 28 was the secretary at a car dealership.

A mutual love of sports brought the two together.

He had been the same sports that she had been in,

and they loved showing their scars off, each of them, you know,

and where they got this and where they got that.

And they were a wonderful match.

At 5 a.m. on a November Saturday morning, a friend arrived at Brian Mock's home to pick him up for a day of

hunting.

He said that the house was dark, and so he didn't bother knocking on the door to see if

Brian wanted to go. He just went hunting by himself.

The friend called later that morning, but no one answered. So he drove back over to Brian's

...