This is News Nation, and we're going to play Jim Clementi's theories here.

Down on these pictures, frame by frame, and to try and fill in the blanks on this baffling mystery,

he joins me now to share what he found.

Jim, great to see you.

We should say you were an FBI profiler.

It was your job on tough, cold cases to come in and reverse engineer, try and

figure out who they should be looking for. Let's first take a look at the blood images. The first

one is this image. It's a wide shot of the blood spatter on the doorstep. What does that tell you

when you look at it? Well, it tells a story of a snapshot of time.

There's low velocity blood spatter.

There's medium velocity blood spatter.

And then there's on the right hand side, you see a blood smear.

That means somebody impacted that blood after it hit the floor.

Step on it.

Step on it, rubbed an arm or a hand through it, something like that.

What are the blood drops tell you?

Well, the bigger droplets tell us that because there's no directionality, that they were

dropped almost directly from above.

But the smaller droplets tell a different story.

Which is what?

Well, they're actually medium velocity blood droplets, which means that they were coughed out.

They were aspirated and then coughed out.

...