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Introducing Forensic Science
Ancient Forensics
The first written method including forensic applications came from
ancient China, where a doctor noted it was possible to tell if a per-
son found dead in a pond had died from drowning or had been dead
before being placed in the water. The ability to determine whether a
person died in the water does not provide clues as to the identity of
the killer, but it does indicate whether the death may have involved
foul play. Dead people do not tend to move around much on their
own, do they? Someone had to put the body into the water.
Key Concepts of
Forensic Science
Criminals often think they have committed the “perfect crime.” They work
hard to clean up after themselves and are extremely careful not to leave any
visible sign of their presence. What most criminals do not realize, however,
is that there is always evidence left behind. The basic concept behind all of
forensic science is the Principle of Exchange, put forward in 1910 by a crimi-
nologist named Edmund Locard. This theory holds that every time a person
touches something, he leaves behind a physical trace of that contact. It may
be amazingly small, but the trace is always there. Knowing where to look
and how to collect the evidence is the specialty of a forensic scientist. The
