Most fingerprint analysts work on the mundane aspects of police work --
they locate fingerprints (latents) at the site of armed robberies or residential
But they also work on homicide cases. That means they have to search the
premises for prints. They may also have to take prints from the deceased in
order to make an identification.
Smooth surfaces produce the best prints, so analysts examine door handles
and window and door frames. While a complete print is the ideal find, partial
prints can also be identified. Some criminals even have footprints on file,
so a print in blood can't be overlooked.
A fingerprint analyst uses a variety of powders to dust surfaces -- light
colored powder on dark surfaces and dark powder for light surfaces. The prints
are "lifted" off with the aid of sticky tape and then transferred to paper.
Everything must be preserved in pristine condition in anticipation of a
future court case -- right down to the sticky tape itself, which will prove
any future match is legitimate.
The fingerprint is then brought to a lab and matched to a file of known
local criminals. If no match turns up, analysts search the international fingerprint
database -- an automated fingerprint identification system -- to locate the
print. If there's a match, then the original and the print from the database
are placed side-by-side and entered as an exhibit during trial.
The analyst can be called by either the prosecution or the defense and
must be able to convince the jury of their findings. A fingerprint can make
or break a case.
Not all fingerprint analysts are police officers. In the U.S., analysts
are usually civilians. Whether they attend the crime scene or not varies from
one agency to another.
American police departments are notoriously understaffed. Donna Jewett
is supervisor of the central identification unit at the San Jose Police Department.
She is also chair of the International Association of Identification's
(IAI) fingerprint analysis committee.
"We have a tremendous shortage," says Jewett. "They're recruiting
at the college level."
The big problem for Jewett is finding people with the training. With California's
high cost of living, few experienced people are willing to transfer. Instead,
she has to find people capable enough to put through training.
"For entry-level positions, we usually take people from the records department
because they have some background knowledge."
Trace criminals' fingerprints