Dr. Tracey: We have no stake in the outcome, on whether somebody's found guilty or innocent.

(Local news report)
Tonight: Police say two suspects are behind bars for the killings of a young couple...

It's a major break in a high-profile case -- the double homicide of Ashley Yennes and Anthony Howzee, the two lovers shot to death in a car.

Dr. Tracy Corey performed their autopsies as part of the police investigation less than a week earlier.

Now, authorities say they know what happened in that alley and why.

Friday, Feb. 9: Louisville police headquarters
Under arrest are two young men, a 17-year-old and a 19-year-old who, police say, had been hanging out with the couple on the afternoon of the murder, though they'd denied having seen Ashley and Anthony when the police questioned them.

Chris Middleton (lead detective): You got somebody that's lying to you. And you know it. And there's a reason why they're lying to you.

Police say they had proof the men were lying. A surveillance tape from a convenience store shows the four of them together just hours before the murders.

Det. Chris Middleton: Those cameras, they're not capable of lying. They show what they see and tell what they see.

Middleton says seeing the tape broke the suspects down. But each accused the other of being the shooter. He says the motive for killing Anthony was robbery, and that Ashley was shot just because she was a witness.

Angela: He's a coward. And I'm very angry at him. She was just 18. Just turned 18.

So far, police have not found a gun, so the pristine bullets Dr. Tracey Corey carefully extracted in her forensic examinations have not been matched to a weapon -- yet.

Victoria Corderi: Eight days after the bodies were found, the detectives made two arrests in the case. How did that make you feel?
Dr. Tracey Corey: I'm happy for the families that that will help them get some closure, but my role does not involve being emotionally invested on whether or not someone is charged with a crime, whether or not someone is guilty or innocent. A good forensic pathologist remains impartial.

Her job, she says, is representing the victim by analyzing what happened in the last minutes of life.

Dr. Corey: I testify when subpoenaed by either side, and I testify, basically, as to what the victim told me.

A month later, another case that had been through Dr. Corey's autopsy room reached its conclusion as well.

Tuesday, March 6: Criminal court

(In court)
Judge: All right. Am I saying your last name correctly, K-e-r-r?
Kerr: Yes, your honor.

Remember, Clayton Kerr had made a deal before he confessed to murdering and burying Roy Jeffries.

But the medical examiner's office first had to determine if Kerr was telling the truth about how he killed and buried Jeffries. The autopsy backed up Kerr's story so it was time for a judge to sign off on Kerr's plea bargain -- a 20-year sentence -- of which he must serve 17 and a half years for manslaughter.

(Courtroom)
Judge: Are you pleading guilty because you are guilty and you make no claim of innocence?
Clayton Kerr: Yes, your honor.

The victim's parents had reluctantly agreed to the deal. Still, they could barely contain their anger.

Margaret: I want to know what makes him think he's god. Why would you do such a stupid thing? What puts it in a person's head that just because you don't get what you want, that you just go kill somebody?

It turns out Kerr had an accomplice the night he buried Jeffries -- his girlfriend, the woman he thought Jeffries was trying to steal from him. She was in court too.

Judge: So, is-- is your full name Savannah Marie Meeks?
Savannah Marie Meeks: Yes, ma'am.

In her own videotaped confession, Meeks admitted to police that hours after the murder she went to the woods with Kerr and shined a flashlight while he buried the body.

(Confession video)
Meeks: I held the flashlight while he started digging the hole.

And so she faced a charge of tampering with evidence -- the body. She says she did it because she wanted to protect the man she loved.

(Confession video)
Detective Jason Propes: Did you ever think about calling the police or anything like that?
Meeks: Part of me wanted to because I knew it was wrong … but, you know, part of me, which was stronger, just didn't want to lose Clayton … Didn't want to get in trouble.

In all, during our week in Louisville, the medical examiner's office performed 34 autopsies, including 10 fire victims, the young couple shot in a car, and the bizarre case of a man killed and buried for, of all things, flirting.

Dr. Corey: Humans can be quite creative in the ways they can actually end up causing the death of someone else.

But for Tracey Corey, each death is more than just a case -- it's a life left behind. She listens to the dead, she says, so she can help the living.

Dr. Tracey Corey: We're really dealing with living people who have experienced tremendous loss and tragedy. And we have to be compassionate. They're still going to be grieving, but if I can help answer questions for them, that puts their mind at ease. Hopefully, it will eventually help them accept what has happened, and be able to then move on with their life.

Dateline NBC would like to give special thanks to the families of the deceased who gave us permission to show the final stories of their loved ones

One final note in the case of that young couple. The two suspects arrested for the crime have pleaded not guilty to capital murder charges.

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