M. William Phelps

If you think of the victim as the bullseye on a target, those closest to him are the first ring around the bullseye, and you need to speak with them first.

Family is obviously number one, but that would go along with making the death notification.

So Locke reached out to Dr. Schwartz's employer and those he worked with.

Schwartz had worked on early DNA sequencing that could actually help solve his own murder.

Back in 1978, Schwartz co-authored a white paper with Margaret Dayaw, science which had set the stage for identifying individuals by their DNA.

So if Schwartz's killer had left his or her DNA at the scene with no obvious witnesses to the murder, this research he had done to prove individuality would help law enforcement prove who had killed him by narrowing down a potential suspect pool to one person.

When I was standing along the road leading down into the Schwartz residence, it occurred to me that the road itself then, a dead end, for anyone driving down it, they either lived there, had been invited there, or might have gotten lost and wound up on the road inadvertently.

It's not one of those roads you just pass by or stumble upon.

Detective Vincent D. Benedetto had been with the Loudoun County Sheriff's Office for 15 years when the Schwartz investigation began.

D. Benedetto's expertise is documents, following the paper trail of murders and financial crimes.

And almost immediately, as he begins thinking about the crime scene, D. Benedetto's thoughts go toward motive.

Then something comes up.

The pathologist confirms by late into the night of the 10th that Dr. Schwartz had actually been murdered on Saturday, December 8th, probably in the evening.

So Schwartz had been dead for two days before his body was discovered.

And the pathologist reveals something else, the weapon.

They are now almost certain was not a knife, but a sharp, slightly curved object, definitely similar, but with a much longer blade.

This changes the game for investigators.

Now they need to look back and focus on two days before Schwartz's body was found, which can often complicate matters.

Effectively, your killer is now two days ahead of you.

At 57 years old, Dr. Robert Schwartz was one of the most respected scientists in his field.