![](bg2.png)
by following the current BPA guidelines, investigators
use their experience to manually identify blood spat-
ter patterns and perform geometrical measures to lo-
cate the point of origin, i.e. the spatial location where
the identified bloodstains has been originated. The
collection of points of origin is then used by investi-
gators to try to determine the full dynamics of events
at the crime scene.
This position paper is aimed at proving that com-
putational intelligence methodologies can be effi-
ciently integrated with image processing techniques
to support forensic investigators in increasing their
performance in applying BPA, both in terms of time
and accuracy of analysis. In particular, image pro-
cessing techniques can be used to capture pictures
from a crime scene, remove noise, register that pic-
tures and extract the collection of features that com-
putational intelligence methods can efficiently anal-
yse to make BPA faster and more precise than cur-
rent manual approaches. A preliminary study involv-
ing the application of fuzzy clustering for reproducing
the well-known string method has been carried out in
order to validate our opinion and stimulate computa-
tional intelligence community to face this new chal-
lenge towards a formal definition of Forensic Intelli-
gence.
2 BLOODSTAIN PATTERN
ANALYSIS
Blood is one of the most significant and frequently en-
countered types of physical evidence associated with
a violent crime (James et al., 2005). Consequently,
forensic investigators use a formal methodology, the
BPA, to assesses bloodstains left at crime scenes by
using an approach based on visual pattern recognition
(Brodbeck, 2012). Thanks to this visual approach,
BPA investigators analyse the size, shape, and distri-
bution of bloodstains resulting from bloodshed events
in order to determine the types of activities and mech-
anisms that produced them. In particular, BPA may
provide several types of information to forensic in-
vestigators as, for example (James et al., 2005): 1)
areas of convergence and origin of the bloodstains,
2) type and direction of impact that produced blood-
stains or spatter, 3) mechanisms by which spatter
patterns were produced, 4) assistance with the un-
derstanding of how bloodstains were deposited onto
items of evidence, 5) possible position of victim, as-
sailant, or objects at the scene during bloodshed, 6)
possible movement and direction of victim, assailant,
or objects at the scene after bloodshed, support or
contradiction of statements given by accused and/or
witnesses, 7) additional criteria for estimation of post-
mortem interval. Moreover, BPA is used to shed light
on other forensic matters such as differential diagno-
sis of homicide/suicide/accident and identifying areas
with high likelihood of offender movements for tak-
ing DNA samples.
BPA activities are based on a bloodstain classifi-
cation from S. James, P. Kish and P. Sutton (James
et al., 2005) which divides bloodstains into three cat-
egories, passive/gravity, spatter and altered based on
stain physical features of size, shape, location, con-
centration, and distribution (Brodbeck, 2012). In de-
tail, passive category describes bloodstain patterns
that are formed under the influence of gravity. This
group includes contact stains, which result from con-
tact between two surfaces, of which at least one has
blood on it. Contact stains often provide information
about sequences of movement. Flow patterns, pool-
ing/saturation and drip stains also belong to this cat-
egory. Spatter category includes spatters that result
from active events such as a shot, as well as spatters
that are caused by, for example, expiration or cast-off
from objects that are swung. Altered category con-
tains all further stain types, such as blood clots and
diluted blood that results from the addition of other
liquids.
All the BPA analysis depends on the fact that
blood is a complex non-Newtonian viscoelastic fluid.
For this reason, a drop of blood tends to form into
a sphere rather than a teardrop shape when in flight.
Ideally, once the sphere lands on a flat surface, the
collision flattens the liquid creating an elliptical or cir-
cular stain depending on the angle of impact. The an-
gle of impact is the angle at which a blood droplet im-
pacts a surface, measured with respect to a imaginary
line perpendicular to that surface. In particular, the
more acute the angle of impact, the greater the elon-
gation of the bloodstain as the width decreases and the
length increases (James et al., 2005) (see Fig. 1).
Figure 1: Elongation of bloodstains in terms of the angle of
impact
1
.
Starting from the aforementioned bloodstain clas-
sification and the physical features of blood, BPA an-
1
http://science.howstuffworks.com/bloodstain-pattern-
analysis3.htm
FCTA2014-InternationalConferenceonFuzzyComputationTheoryandApplications
212