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Anthropologist
Henry Schwarcz is a master
at reading the signatures
left by food in people's bodies.
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He
can trace life histories through
atoms laid down in a body,
deducing where someone lived,
what they ate and how they
moved around.
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The
researcher from McMaster University
in Hamilton, Ontario, usually
studies human remains from
archeological digs and ancient
graveyards.
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But
his work has just been used
in an entirely different way,
and the results promise detectives
a powerful new crime-fighting
tool.
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Mr.
Schwarcz needed just one strand
of hair to reveal to U.S.
detectives that an unidentified
murder victim was not Asian,
as suspected, but Mexican.
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"I
knew it within minutes of
getting the first reading,"
said Mr. Schwarcz of his first
foray into assisting police
work.
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His
work has so impressed U.S.
homicide detectives that the
officers predict such atomic
profiling will become an integral
part of investigations involving
unidentified bodies.
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"Dr.
Schwarz's techniques are ground-breaking,"
said Detective Paul Dostie
of the Mammoth Lakes Police
Department in California.
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"You
won't see any of this on CSI
because it's never been done
before," he says, referring
to the popular television
show.
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Det.
Dostie and his colleagues
have spent two years trying
to solve a murder in the small
Mammoth Lakes community in
the Sierra Nevada Mountains.
A woman's remains -- and her
clothes and still working
wristwatch -- were found in
a shallow grave near the Shady
Rest Campground in the spring
of 2003.
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Police
initially identified the victim
as a tiny Asian women about
four foot six inches tall,
and 30 to 40 years old. They
suspected the woman might
have been a "mail-order" bride
murdered by an abusive husband.
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That
led nowhere and Det. Dostie
and his colleagues turned
to the scientific community
for new leads. Researchers
in several labs offered to
help extract clues from the
victim's DNA, remains and
wounds.
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Mr.
Schwarcz, who often collaborates
with one of the U.S. anthropologists
working on the case, was asked
to examine the victim's hair
to find out about her diet.
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"You
are what you eat," said Mr.
Schwarcz. "You're made up
of a whole bunch of atoms
and every one of them had
to enter by your mouth and
go down your gullet."
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The
police couriered 20 strands
of the victim's hair to Mr.
Schwarcz's lab in Hamilton.
One hair was snipped and fed
to a mass spectrometer that
measures different forms of
elements, known as isotopes.
The isotopes of carbon vary
with foods, with corn, rice
and wheat all leaving a distinct
isotopic signature. Oxygen
and hydrogen isotopes also
vary markedly in water across
North America. Someone growing
up in Toronto will have a
different isotope ratio in
their bones than someone from
Los Angeles.
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Mr.
Schwarcz found the victim's
hair bore the striking carbon
isotope signature left by
a heavy diet of corn. And
it revealed she ate little
or no seafood in the year
it took the hair to grow.
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Mr.
Schwarcz then offered to take
it a step farther and see
if he could figure out where
the victim had lived throughout
her life. The police couriered
one of the victim's teeth
and a rib bone to Hamilton.
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The
tooth, which would have formed
about age six, had the water
signature of a youth spent
in the southwestern U.S. or
northern Mexico. It also revealed
she lived on a diet of almost
pure maize -- a poor diet
for a growing child, which
could account for her small
size.
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The
rib bone, which grew later
in life, showed the women
spent about a decade in southern
Mexico or Guatemala where
the water left its signature
in her bones. "That's the
only place you'll find the
isotope oxygen-18 quite as
abundant as that," said Mr.
Schwarcz.
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"This
was a women who had been moving
through her life," he says.
"We don't know the exact story
of course but it looks like
a person from a Mexican family
who have been in California
and then migrated back home
to southern Mexico or Guatemala."
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A
detailed DNA analysis done
is a U.S. research lab pointed
in the same direction, revealing
the woman was a Zapotec Indian.
They traditionally lived in
Oaxaca in southern Mexico.
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"She
didn't have a drop of Asian
blood in her," says Det. Dostie.
The women full identity is
still unknown. And her husband,
who is the key suspect, has
not been found.
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But
Det. Dostie says the scientific
sleuthing has enabled authorities
to produce a facial reconstruction
and issue an update on the
investigation that has become
a test case for the "powerful"
new profiling technique.
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"It
gave us a tremendous amount
of new information," Det.
Dostie said.
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Mr.
Schwarcz is now back studying
ancient bones but is open
to more forensic work. "We
know now we can do this, so
if another case likes this
turns up we will be able to
figure out where the victim
came from," he said. "I'm
not advertising, but if the
phone rings..."
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©
National Post 2005
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