ppt 2
DESCRIPTION
case study of a murder case solved using glass as a evidenceTRANSCRIPT
SUSPECT: MR. LAND VICTIM: MS.BROWN.
Trace evidences: hand gloves, shoes of the suspect, shattered
glass pieces of the house window and car window.
Ms. BROWN goes missing
Police officers from the Birmingham department visited the
site
Things noted:
i. All the doors and windows of the house were locked
ii. The window located near the rear entry of the house had
been broken
iii. The driver’s side of the car window was shattered.
iv. Shoe imprint was found on one of the glass pieces.
v. Very important - her body was found by hikers in a rock
quarry on Ruffner mountain in Jeffferson country.
Following the clues i.e contact numbers of Mr.LAND and
his mother were found on the bulletin board.
Mr.LAND accompanied the police officers and they found the
imprint of shoes matching the evidences.
They even ceased two wire cutters from his car.
Later they ceased, hand gloves of LAND.
Bloodstains were found in his shoes.
Glass pieces from different locations were packed into
different containers(clearly marking the outside package the
description of the evidence)
Depending on the size, glass pieces was packed in envelopes,
bags, or in paperfolds.
Rear glass window of the house hand gloves
of the suspect
SAMPLE location
G1 Fragments of rear window
of the house
G2 Fragments found on the
car seat
G3,G4 Hand gloves of the
suspect
KS1 Glass pieces of the rear
window
KS2 Glass pieces of the driver
side window
The shattered car window pieces
The composition of a particular piece of glass is unique
Glass being made up of a variety of compounds, it is
possible to distinguish one type of glass from another
by examining the different physical and chemical
properties.
During investigations, glass forms one of the
evidentiary materials in many criminal cases.
The significance of such evidence will be enhanced if
the fragments are determined to be indistinguishable in
all measured properties from the broken window.
GLASS IMPORTANCE IN CRIMESCENE
Glass is technically defined as: “The inorganic product of
fusion which has cooled to a rigid condition without
crystallizing”
Due to its fragile nature and abundance, glass is one of the
major types of trace evidence encountered in crime scenes
such as burglaries, car accidents, hit and runs, assaults, drive-
by shootings and bombings.
Whether it’s a glass or no?
The physical properties used for comparison include glass
color, fluorescence, thickness, surface features, and curvature
These tests are rapid and nondestructive.
Color assessment is performed visually against a
white background in natural light with the particle on
edge.
Side-by-side comparison should be used with
similarly sized particles
THICKNESS CURVATURE
The ratio of the mass of an object to the volume occupied by
that object. (g/cm3 ,solids); g/mL (liquids))
Each type of glass has a density that is specific to that glass.
If two samples of glass can be differentiated by density, they
could not have originated from the same source.
Glass density can be measured by Displacement, Flotation,
and Density Gradient Column methods.
SAMPLE DENSITY
Group 1 2.532 g/cm3
Group 2 2.425 g/cm3
Group 3 2.533g/cm3
Group 4 2.432g/cm3
Known sample 1 2.53g/cm3
Known sample 2 2.42 g/cm3
Refraction is the change in the direction of light as it speeds up or slows
down when moving from one medium into another
It is the most commonly measured property in the forensic examination of
glass fragments. It provides good discrimination potential.
BECKE LINE - If the refractive index (n) of the liquid medium is
different from the refractive index of the piece of glass, a halo-like ring
appears around the edge of the glass.
SAMPLE REFRACTIVE INDEX
Group 1 1.520
Group 2 1.5188
Group 3 1.521
Group 4 1.5190
Known sample 1 1.520
Known sample 2 1.5188
Nowadays, refractive index methods are semi-automatic – the GRIM2 instrument measures
the refractive index of glass fragments by reference to calibrated immersion oils and
automatically identifies the glass.
• Glass composition can be analyzed.
•Manufacturers of the glass can be identified.
•The time period ,when it was manufactured can be identified.
ADVANTAGES:
•Accuracy, time
DISADVANTAGES:
• Cost, distraction of the sample
SL.
no
Na2
O
Mg
O
SiO2 SO3 Ca
O
Cr2O
3
K2O FeO Al2O3
G1 14.0 3.7 73.1 0.2 9.0
G2 13.1 3.5 73.3 0.2 8.3 0.6 1.0
G3 14.0 3.7 73.1 0.2 9.0
G4 13.1 3.5 73.3 0.2 8.3 0.6 1.0
KS1 14.0 3.7 73.1 0.2 9.0
KS2 13.1 3.5 73.3 0.2 8.3 0.6 1.0
RESULTS OF SEM ANALYSIS
Sl.no Fe(Kα) Sr(Kα) Sr(Kβ)
And/ or
Zr (Kβ)
Nb(Kα) Other
peaks
G1 93 41 26 - -
G2 65 42 45 - -
G3 93 41 26 - -
G4 65 42 45 - -
KS1 93 41 26 - -
KS2 65 42 45 - -
RESULTS OF XRF ANALYSIS
After the analysis:
• the glass pieces found in the suspect hand gloves
matched the
1. Rear glass pieces of the window
2. Glass pieces of the drivers seat of the car
• The shoe print found in the spot matched the suspects
shoe print.
• After the analysis we found some blood stains in the
shoe.
RE-CONSTRUCTION
•The proof prooved that he is the culprit.
•Later on interogation he confessed that ,
he shot her from the back , but later he
ran away.
•Since we found the blood stains in his
shoe , turned out to be the major
evidence.
JUDGEMENT:
Michael jeffrey land was convicted of
the capital murder of candance brown,
and sentenced to death.