Bodies that are displayed can be found easily by police. The killer isn't trying to hide them. Some of the victims in the Atlanta child murders decades ago were displayed out in the open. The killer wanted them to be found that way. It was basically his way of saying: "I'm presenting my trophy here. Screw you, law enforcement. Try to catch me if you can."

Displays are usually directed at the authorities. Posing tends to be more personal. It's about the victim.

Convicted killer George Russell posed his victims in Seattle. He used what we call artifacts, or instruments, to pose the naked victims in sexually explicit ways. One woman was posed with a shotgun between her legs and another with a sex toy in her mouth. They were set up in a degrading manner, illustrating the killer's way of thinking: "These women are nothing but a bunch of whores."

Anger and hostility

This tells you something about the subject you're dealing with -- his anger and hostility. In the Atlanta case, it was more of a cat-and-mouse kind of game with police.

Then you have killers like Steven Pennell in Wilmington, Del., who lured prostitutes to his van, tortured them, kept them for a while and then dumped them like trash -- which is what he thought of them. No posing, no props.

So the intent varies, depending on the subject. You have to look to see what the message is.

Sometimes you'll see a victim laid out nice and neat at a crime scene. The subject may go so far as to cover the corpse with a sheet or blanket.

There are various reasons for doing this. The killer may go into an explosive rage and then ask himself afterward, "What did I do?" He doesn't want to look at the crime he perpetrated, so he covers the victim.

When a parent kills a child

Or it could be that a close relationship existed between the killer and the victim. Let's say a parent kills a child and then buries the body. You may find that the child was carefully wrapped or the face covered to keep dirt from getting in the mouth. In essence, someone is caring for the child after death.

There's a word we use: "undoing." That's when someone tries to somehow lessen the damage after committing the crime, maybe by cleansing and bandaging the wounds. The killer may try softening the appearance of the crime by making the body's position restful and clasping the hands, almost like the victim is laid out. It's a way of symbolically erasing or reversing the crime, and it suggests remorse. Doing this gives the subject away. It's a personal crime -- strangers wouldn't likely do this.