Unfortunately, in 2001 about forty percent of murders weren't solved, or rather, in more of forty percent of murders the perpetrator didn't go to jail. So all of those could be considered "perfect" murders because the perpetrator wasn't held accountable. With increasing advances in forensic science, however, more murderers should be identified. The most important person in any murder investigation, now, is not the scientist in the laboratory but the first police officer at the crime scene; because it's his or her job to protect the crime scene evidence from contamination. Unfortunately, even today most crime scenes are compromised by people -- people who shouldn't be there -- walking through and contaminating the evidence. It's one of the main reasons that a perpetrator isn't caught.

But as we make progress in the ability to identify and compare trace evidence -- such as hairs, fibers, saliva, blood and semen -- at a crime scene and match that evidence to a perpetrator, there will be more bad guys caught. It's important to point out that not every crime scene has trace evidence, though. So I doubt there will ever be a time when every murderer will be caught. We can increase our ability to catch murderers, by doing our jobs right and protecting the crime scene evidence from contamination or destruction; gradually we'll get better and better crime resolution rates, meaning fewer "perfect" murders.

You have said that it's not your job to catch the killer but to determine what happened. Do you ever, or have you ever, had a hard time dividing the two?

Yes, I do have a hard time, sometimes, in dividing between determining "who done it" and what happened. It happens to me most often in cases of baby deaths, especially those of battered children, particularly children who've been murdered by a caregiver. That's because I realize that in those situations it's not only necessary to catch the perpetrator for punishment purposes, but also to prevent future crimes against children. Very few murderers of adults are recidivistic, that is, kill repeatedly; most murders happen between people who know each other, and usually in the heat of the moment. And there are professional killers who are repeat murderers. But child abuse is a crime that has a great likelihood of being repeated, and the victims are surely among the most innocent of all murder victims. So I do have a hard time dividing between determining what happened and identifying the person who did it.

Can someone die of arsenic poisoning but show little or none of it in the body?

When it comes to arsenic poisonings and other heavy metal poisons like thallium, for example, in order to cause death there has to be a lot of the poison in the body. One should be able to find it in the body, even in the hair, because the hair concentrates and retains these poisons. This holds true for most poisons; they only kill by accumulating in the body at high levels and they tend to stay there after death. There are some poisons that disappear after death, and some poisons that we can't yet identify; it requires new technologies to identify them.

But when it comes to arsenic (and many of the traditional poisons like strychnine), when there's a poisoning the poison should be identifiable in the body. The one exception is cyanide poisoning, where a person can die of cyanide poisoning but the cyanide may not be able to be found after death. As time passes, cyanide may not be able to be found in the body, but other poisons like arsenic will be able to be found.

How can you tell that a body has been moved post mortem?

The usual way we determine whether a body has been disturbed after death is to look at whether the signs of death are in their natural position. That is, when we die, the body goes immediately into a gravitational position -- a position determined by gravity -- such as a standing body will fall to the ground, for example. The whole body collapses as a result of gravity and then, over a period of an hour or two, rigor mortis starts to become noticeable and the muscles and the arms and extremities start getting stiff. At the same time, after death, the red blood cells in all the blood vessels of the body start settling down to the lowest point, much as red cells settle in a plastic bag when one gives blood at the blood bank.

The blood is about forty-five percent red cells, white cells and platelets -- solid material -- and during life the heart churns it all up, so everything is all mixed together. But as soon as we die, everything starts settling in the body because there's no more churning action. This causes a reddish, maroon color of death, called lividity. So if after an hour or two the body is moved and put in a different position, rigor mortis and lividity will still reflect the body's original position.

That's one of the things we look at very carefully to determine whether the death scene is a primary death scene or a secondary death scene. The primary death scene is this the place where the person died, and if the body's been there, undisturbed, until investigators arrive, the rigor mortis and lividity should be in a certain gravitational position, determined by body position. If the body has been moved to another position -- a secondary position -- unless it's positioned exactly as it was originally, or moved within less than an hour after death, we'll be able to tell.

Also, if there's a break in the skin -- if the person has an open wound that would have bled profusely -- but there's no blood at the scene, that certainly would also indicate that the body's been moved. And sometimes we can tell by the types of flies and maggots that settle on the body whether it's been moved from an indoor location to an outdoor one. For example, if a person is killed and put into the trunk of a car, flies should not be able to get to the body. So, If we find maggots on the body in the trunk of the car, we know that the person died outside of that trunk -- someplace where flies could get to the body and lay eggs on it -- and then put into the trunk afterwards. If the person dies in the trunk or has died and then been placed immediately in the trunk, there shouldn't be any flies or maggots on him.

Do you ever speak at universities? If so does one contact you?

Yes, I do speak at universities and find the students to be very enthusiastic about the burgeoning new forensic sciences. The best way to contact me would be by contacting HBO and they'll forward the request to me.

Can a person literally be frightened to death?

Yes, a person can be frightened to death. In fact, somebody can suddenly scare somebody else, who collapses and then dies. But that only happens when that individual has a preexisting heart disease or hardening of the arteries to the heart (coronary arteries). He or she is then at risk of getting a fatal cardiac arrhythmia when undergoing physical or emotional stresses. This happens because the heart can't beat fast enough and sets off bad electrical signals, triggering a fatal cardiac arrhythmia. When someone is suddenly frightened, that can trigger a fatal cardiac arrhythmia in somebody who has a preexisting hardening of arteries of the heart.

We just recently had a situation where somebody came into a store with a gun and held up the storekeeper. The storekeeper, an elderly gentleman, looked at the gun and was terribly frightened, collapsed and died.

When we did the autopsy there was no evidence of trauma or injury, but there was evidence that he had a bad heart and that the fright of seeing the hold up man caused him to collapse and die. So even though the death was a natural death, from natural heart disease, the district attorney charged the hold up man with murder because his action -- scaring the storekeeper -- shortened the man's life.

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