Andrea Canning

But within moments, Lars became frantic, hyperventilating, moaning.

The question, was it for real?

And investigators also noticed how Lars' story evolved over just a few hours.

On the 911 call, he set the scene this way.

To responding officers, he changed the order of events, telling them he saw that light after he got out of bed.

In his interview down at the station, Lars revised his story again.

That's when he said he woke to the front door squeaking and offered, for the first time, this description of how he realized he'd shot Debbie.

During those interviews, Lars appeared heartbroken, at times falling apart.

He was described as pacing in the blanket.

He was mumbling, moaning.

Is that not what a husband should do after something like that?

It sounds normal.

These bits of emotion are only done in front of the detective.

What was he doing when officers were not watching him?

And sipping his signature drink, Dr. Pepper.

Free on bail, Lars understood he was still under the microscope.

Watching Lars suffer was torture for Ken and Christy.

They knew how much their brother loved Debbie and how dark and confusing that house could be at night.

You felt it was important that we come to the house now.

Yes, I did.