Expert Witness Journal Issue 65 February 2026 - Flipbook - Page 12
being deposited. However, all is not lost, as low
quality and partial prints can be used to establish
someone’s identity - as long as the recovered print
contains enough information.
You may also 昀椀nd you have additional SFRs to deal
with if other marks are compared at a later stage.
These additional marks are often relied on if an
individual enters a not guilty plea.
Analysing 昀椀ngerprints - opinion not fact
When 昀椀ngerprint evidence is classi昀椀ed as
inconclusive, legal teams can bring in a 昀椀ngerprint
expert to carry out their own analysis of the marks.
The SFR is only ever a starting point. It provides basic
information that can be explored and potentially
challenged by a 昀椀ngerprint expert in two common
ways.
Although 昀椀ngerprint evidence was presented in
court for many years as fact, the forensic regulator
now classes the evidence as expert opinion. Even
when experts work in the same organisation and use
the same equipment, techniques and approaches,
they can make di昀昀erent judgements on the same
evidence.
Context
Marks used to identify the presence of someone
at a scene. For example, someone who lawfully
visited the scene could have left a 昀椀nger, thumb or
palm print in a location and at an orientation that
eliminates them from the inquiry.
When 昀椀ngerprints are analysed and compared, the
outcomes can be classi昀椀ed into four di昀昀erent groups:
1.
Identi昀椀ed - the mark can be con昀椀dently
attributed to a particular individual as there
is su昀케cient quality and quantity of 昀椀ngerprint
detail for the 昀椀ngerprint practitioner to assess
and match.
2.
Excluded - enough 昀椀ngerprint features do not
match to conclude that marks did not come
from the same person.
3.
Inconclusive - the 昀椀ngerprint mark does not
contain enough and/or su昀케cient quality detail
for a viable comparison and gives inconclusive
results.
4.
Insu昀케cient - the 昀椀ngerprint mark contains
such low quantity and/or poor-quality detail
that a reliable comparison cannot be made.
The detail is not clear enough or it has been
so compromised by external forces that the
evidence is unreliable.
Length of time
The moisture content of a 昀椀ngerprint can have a
major impact on the length of time the mark lasts
upon a surface. Watery sweat typically evaporates
fairly quickly, whereas fatty sweat - or sweat which
combines water and fat - can last longer. Sometimes
this can be weeks or months rather than days
depending on the level of disturbance (like cleaning
or movement of material against the print).
Once a 昀椀ngerprint is deposited, the length of time it
persists on a surface is in昀氀uenced by:
•
Its composition
•
The amount of matter deposited
•
The physical properties and condition of
the surface
•
The degree of handling or disturbance
Opportunities to challenge
昀椀ngerprint evidence
•
Its position
•
The environmental conditions
When you receive a streamlined forensic report (SFR)
issued by a 昀椀ngerprint bureau, it will report initial
昀椀ngerprint evidence 昀椀ndings. However, because
di昀昀erent bureaus record di昀昀erent information, the
information on the SFR can vary and may not give
you the full picture.
As each of these factors are variable there is currently
no reliable technique to accurately determine the
age of a latent 昀椀ngerprint.
Information you might expect to see includes:
A 昀椀ngerprint identi昀椀cation is open to challenge and
can occasionally be found to be wrong. As in the
case of a 昀椀ngerprint found at the scene of a serious
terrorist incident in the US. The print was matched to
one on a computer database and the match veri昀椀ed
by three experts. However, this was later found to
be wrong. So, although rare, misidenti昀椀cations can
happen.
A specialist should be able to explain the limitations
of 昀椀ngerprint evidence to a legal team or jury.
•
•
•
What can in昀氀uence 昀椀ngerprint
analysis outcomes?
Which 昀椀nger, thumb or palm print at the crime
scene has been identi昀椀ed as the crime scene
mark.
The origin of the crime scene mark - this is not
always clear, but it should include a crime scene
number.
Details of other marks previously identi昀椀ed in
the case - you’ll likely 昀椀nd these on later pages
of the SFR.
EXPERT WITNESS JOURNAL
10
FEBRUARY 2026
