Up next, a violent thunderstorm provides cover for a brutal murder.

It was an absolutely brutal crime scene.

Obviously, this was a case of an overkill.

There are plenty of suspects with clear motives, but they all pass polygraph tests.

It's not 100% reliable.

If investigators didn't find the one tiny clue left at the scene, they might never have solved it.

The real estate development business in Texas always seems to be active.

Darrell North, a manager for a multi-billion dollar development company, had no shortage of work.

Darrell North was in charge of building budget suites for a company out of Las Vegas,

and he had been in charge of building several in this area.

Darrell had a reputation as a fair-minded boss who set high standards.

I asked a subcontractor, was Darrell hard to work for? Was he mean? And he said, no, he was not. He said he expected quality work.

I've seen dad fire numerous subcontractors over the years. My dad had the ability to get his point across very clearly.

He's very pointed.

He was very direct.

Daryl was always punctual.

So when he didn't come home from work one day and didn't answer his phone, his family was concerned.

When I got to the job side, it was after 11 o'clock at night.

The lights of his trailer were on, and his car was out front,

and I knew his car hadn't been moved because it was dry underneath his vehicle,

and whatever else was just drenched.

The door was padlocked.

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