Locard's Exchange Theory

Professor Edmond Locard wrote the following in the early years of the twentieth century:

Wherever he steps, whatever he touches, whatever he leaves, even
unconsciously, will serve as a silent witness against him. Not only his
fingerprints or his footprints, but his hair, the fibers from his clothes, the
glass he breaks, the tool mark he leaves, the paint he scratches, the blood or
semen he deposits or collects. All of these and more, bear mute witness against
him. This is evidence that does not forget. It is not confused by the excitement
of the moment. It is not absent because human witnesses are. It is factual
evidence. Physical evidence cannot be wrong, it cannot perjure itself, it cannot
be wholly absent. Only human failure to find it, study and understand it, can
diminish its value. - Professor Edmond Locard http://en.wikipedia.org/wiki/Locard%27s_principle

Locard was primarily focused on trace evidence of a physical nature, yet, I would argue that the perpetrator or perpetrators of a crime or series of crimes leave their victim or victims with trace evidence that is not visible to the eye. I would argue that these latent traces are left on the minds, hearts and very souls of victims.

I would also argue that the converse is also true in that I would that victims of crimes leave invisible marks on the perpetrators of crimes that when discovered confirm the guilt of the criminal.