forensic science

1. - By,
( Student of M.A. in Police
Administration, Sem.-1 in Raksha
Shakti University)

2. introduction
 Crime scene:- any place where the crime has
occurred or the possibility that the crime might
have occurred at that place is called as crime
scene .
 The crime scene is basically divided in two
types according to the place.
 1)primary crime scene:-the actual place where
the crime has taken place

3. Cont.
2)Secondary crime scene :-any optional or other
place where there are chances of finding some
evidences related to the crime.

4. Two type of crime scenes
 indoor
-70% of all crime scenes
-normally located within a residence
-can occur within a commercial building
Outdoor
-may be a very large area
-parks or residential backyards

5. Major functions of forensics
scientist
 To prove the existence of crime in the court of
law
 To identify the victim and the suspect and
criminal
 To reconstruct the events of a crime

6. The crime scene
 The first officer at the crime scene is
responsible for securing and protecting the
area
 - must first make sure that if the victim is alive,
medics are on their way
 - must secure that the evidence does not get
compromised
 - must make sure that witness do not leave the
crime scene

7. Crime scene investigation
 To protect the crime scene :-
the crime scene should be protected with the
help of police line tape
 What is the first function of the investigation officer
after reaching the crime scene
 -To contact the officer in charge
 -To gather information regarding the persons
having access or have had access to the crime
scene e.g. any protection officer of ambulance fire
brigade etc.
 To decide the physical boundaries of the crime
scene

8. Cont.
 Establish the perpetrator's of entry and exit.
 Do not initial walk through
 Develop a strategy for systematically.
a)examining the crime scene
b)documenting the crime scene investigation

9. Cont.
 Crime scene investigation has based on
scientific method and “Locard exchange
principle “, logic forensic techniques involved
1)recognition- scene survey ,documentation,
collection
2)identification –comparison testing
3)reconstruction-evaluation and interpretation
4)reconstruction-reporting and presenting.

10. Goals are to determine the
following
- what happen
-where did it happen
-when did it happen
-why did happen
-who may have perpetrated these action
-how was the incident carried out

11. Processing a crime scene
 8 universal rules exist
 - safety first
 - secure and protect the scene
 - fulfill the basic legal requirement
 - photograph the scene
 - identify and mark evidence
 - collect label and package evidence
 - diagram the scene
 - write a report

12.  The crime scene investigator has only a
limited amount of time to work a crime scene
 - must photograph the crime scene
 - must sketch the crime scene
 - must take notes
 - must collect ,document , and package
evidence

13. Crime scene recording
 Record the crime scene :– the investigator
must move purposely and record the using a
combination of method including.
 1)photograph :-crime photography is very
important .especially for established physical
relationship items interest like weapons ,
bodies ,stains e.t.c

14. Photography (a picture is worth of thousand words)
 1)Establish overall shots of the scene – this
includes:-
- a) the entire scene
- b) surrounds areas
- c) points of exist and entry
2) area shots showing the general relationship
of items
3) medium ranges shots showing the aspects
and positioning

15. Cont.
 4)close –ups showing details of interest on
evidence items
 5)Make sure to keep a running of all photos
taken
 6)videotape – the use of videotape is being
implemented on a widespread basis in crime
scene investigation recently.

16. Overall photography

17. Mid –range photography

18. Close –range photography

19. Point of entry and exit

20. Cardinal rules for crime scene
photography
 There are three cardinal rules for photography
 1) to fill the frame
 2) maximum depth off filled
 3) to keep the film plain parallel

21. sketches( an annotated picture is worth a ten thousand
words)
 There are two type sketches for crime scene
investigation
 1)rough sketches :- a rough sketch should be
made at the time of the investigation and should
include a simple depiction of all items of interest
in the scene being sketch.
 A sketch will be a small part of an overall part of
crime scene
 It is not drawn to scale .

22. Cont.
 Finished sketch :-the finished sketch is drawn
by a skilled person in drawing in ink ,using
exact measurement.
 The finished sketch need not to be made at
crime scene but can be completed in police
station
 It should be the actual distance , evidence and
objects contained in the rough sketch.

23. Methods of sketching a crime
scene
 There are four methods of drawing sketchs
 1) coordinate method :- this method is
frequently used for indoor crime scene .
 In this method ,focal point is selected and lines
crossing each other at right angle are drawn .
 One line represent the length and width of the
scene to be covered.

24. Cont.
 Base line coordinate method :-in this method,
mark a straight line from one fixed point to
another and call it as baseline, from which
measurements are taken at right angle.
 Take measurements alone either side of the
baseline to a point at a right angle to the object
to be located.

25. Cont.
 Polar method :-this method is used for
sketching large outdoor scenes.
 In this method the distances and the directions
of the objects are noted with reference to a
central focal point.

26. Cont.
 Triangular method :- this method is mainly
used for out door scene but can also applied in
indoor scene.
 in this method , a straight line is drawn from
two fixed objects to the evidence to create a
triangle .
 The angle formed at the location of object can
be measure

27. notes
 Note taking at the scene must be a constant
activity and should be include:-
 A) scene – a detailed written description of the
scene with the location of items of physical
evidence recovered. They should include –
1)Time of discovery and date
2)Who discovered it
3)How it was discovered
4)Who handled the items before packaging
5)Who packaged and marked the item
6)Disposition of item

28. Cont.
 B) details :- this may be the only record of the
scene that exists after a period of time.
 The note taker should put down as many
details as possible at the time the notes are
taken

29. Searching of crime scene
 1)Grid pattern :- the crime scene is divided
into grid .
 The search starts at the beginning of the first
lane , goes to the end and then begins at the
end of second lane
 Best used in large outdoor scene
 Provides a double check of the area.

30. Cont.
 2)spiral search method :- in this method , the
search is started from the focal point of the
crime scene and carried out in a spiral manner.
 used best in outdoor scenes by one searcher.
 Start on outside edge, make smaller
concentric circles as you search.

31. Cont.
 3)zone pattern method :- in this method , the
total area divided into equal squares and each
square area is numbered.
 Best used when there are multiple people
available to search.
 Each searcher is assigned a zone.

32. Collecting and packaging physical
evidence
 1) proper packaging :- the crime scene
investigator should bring several different
types of packaging with them to the scene.
Small packages to contains hairs , fibers ,
bullets , glass or other items should be
available typical types of small packaging
includes –
 A)screw-cap or pressure- lid plastic bottles
 B) small pill boxes
 C) “druggist fold” paper bindles

33. Cont.
 Proper labeling :- once items have been properly
packaged, they must be properly labeling.
 Proper labeling includes the following :-
 1) the investigating agency’s case number .
 2) the scene site
 3) a brief description of evidence
 4) the location where the evidence was obtained
within the scene
 5) the collector’s name
 6) the date and time collected

34. Cont.
 3) chain of custody :- a complete and correct
chain of custody must be maintained for all.
 These include :-
 a) the collecting officer.
 b)the transportation officer
 c) the laboratory evidence collection person

35. references
 1) Dr. m.s dahiya , book ,crime scene
management. page number :- 35
 www.wikipedia. Com
 m.veryshortintroductions.com