Question: What is the significance of glass and glass fragments in criminal investigation?

What is the importance of glass in criminal investigation?

Glass or glass fragments serve as physical evidence of a great value for the investigation of many offenses such as the burglary, arson, hit and run cases, shooting, and assault. A large variety of physical evidences is included under the term “Trace Evidence”.

What is the significance of knowing the characteristics of glass in finding evidences?

Determining the type of glass gives investigators evidence that is considered to have class characteristics. Only in cases where the suspect fragments exactly match fragments from the crime scene is it possible to consider this type of evidence as showing individual characteristics that point to a specific source.

Why is it important to collect all the glass from a scene?

All fragments of glass from a scene should be collected if the aim is to determine the angle or point of impact. The F.B.I recommends that small fragments be packaged in plastic vials such as a film canister.

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How can glass analysis help solve a crime?

Comparing the color of a suspect piece of glass with the color of a reference sample can distinguish whether the two samples share a common source. As a consequence, significant color differences between glass fragments can be used as the basis for exclusion of a suspect.

How are glass fragments collected at crime scenes?

Glass from different locations should be kept in different containers. All glass should be collected because more than one type may be present. … Place small glass fragments in paper bindles, then in coin envelopes, pill boxes, or film cans which can be marked and completely sealed. Place large glass fragments in boxes.

What is glass and glass fracture?

When the tempered glass breaks it breaks into tiny cubes with no sharp edges. … The penetration of ordinary window glass by a projectile, whether it is a bullet or a stone, produces a familiar fracture pattern in which cracks both radiate outward and encircle the hole, as shown in Figure 4-16.

What is glass analysis in forensic science?

Analysis. A forensic glass analysis is typically a comparison of two or more glass fragments in an attempt to determine if they originated from different sources. Less frequently, it is a question of determination of end use, or glass provenance.

What are the two most important physical properties of glass for forensic comparisons?

To compare glass fragments, a forensic scientist evaluates two important physical properties: density and refractive index.

What must a forensic scientist evaluate when examining glass fragments?

Glass examiners compare samples of glass found on suspects or found at the scene of a crime with a suspected source of known origin by measuring the physical and optical properties of color, thickness, density, and refractive index. In most cases, these have been good methods for differentiation between glasses.

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Which characteristic is most important in evaluating the significance of paint evidence?

Which of these characteristics is most important in evaluating the significance of paint evidence? Color, surface texture, and color layer texture. Color Layer Sequence is the most important.