Up next, a masked gunman attacks a suburban family.

Man one whine.

Someone just shot or no one.

He's shot down.

We don't know someone in the map.

This is the most horrible crime I've ever investigated.

The killer leaves several clues.

My first thought with the black glove was not another OJ.

Whoever the crooks were made a mistake leaving behind evidence.

But the forensic evidence reveals something far worse than police ever imagined.

That is a pinnacle moment for me in my forensic career because it doesn't happen that often.

In Sugar Land, Texas, just outside of Houston, everyone knew the Whitaker family.

Fifty-five-year-old Kent Whitaker managed a construction business that had been in the family for a generation.

The business did well. I mean, in construction booms, they did real well.

And when construction wasn't booming, they still held their own.

So it was a great business.

Kent and his wife, Trisha, and their two sons, Bart and Kevin,

were in a festive mood on the night of December 10, 2003.

24-year-old Bart was about to graduate from college

with a criminal justice degree.

They said, let's go out and eat and let's celebrate.

When they returned home from dinner, they were ambushed.

...