A standard/reference sample is material of a verifiable/documented source which, when compared with evidence of an unknown source, shows an association or linkage between an offender, crime scene, and/or victim (e.g., a carpet cutting taken from a location suspected as the point of transfer for comparison with the …
What do you mean by standard reference sample?
Standard/reference sample—Physical evidence whose origin is known, such as blood or hair from a suspect, that can be compared to crime-scene evidence. • The examination of evidence, whether it is soil, blood, glass, hair, fibers, and so on, often requires comparison with a known standard/reference sample.
What is the purpose of standard reference samples?
The collection of standard reference samples important to processing evidence from a crime scene because it can be used to compare the evidence from the crime scene to one’s evidence that origin is known.
What is a substrate sample forensics?
A substrate control is uncontaminated surface material close to an area where physical evidence has been deposited. This sample is used to ensure that the surface on which a sample had been deposited does not interfere with laboratory tests.
What is a standard reference sample quizlet?
A standard/reference sample is physical evidence whose origin is known, such as fibers or hair from a suspect, that can be compared to crime-scene evidence. It is important to a criminalist because it provides the crime lab with some way to compare the evidence to something.
What is the working standard?
Standard that is used routinely to calibrate or check material measures, measuring instruments or reference materials. A working standard is usually calibrated against a reference standard.
What is a standard or reference?
any one of the substances (materials) with precisely known and officially certified values of variables peculiar to a given substance. Owing to their purpose, standard reference materials belong to the class of metrological means known as measures. …
What is a comparison sample?
Examples of Comparison Sample in a sentence
— Comparison Sample: a sample of the same substrate as the samples collected from the origin of the fire, without the suspected accelerant.
What is a comparison sample forensics?
A comparison sample is a sample of a known ignitable liquid at the crime scene collected to be used as a comparison to an ignitable liquid residue found in another sample found at the crime scene.
What is the difference between an unknown sample and a control?
Control samples may come from the victim, from the suspect, or from items found at the scene. … That way, the known or control sample taken from the car can be compared with the unknown sample discovered at the crime scene. A match either puts the suspect at the scene or the victim in the suspect’s car.
Which type of evidence should be collected first?
Collecting prints at the crime scene should be every investigator’s top priority. Fingerprints from the suspect as well as elimination fingerprints from the victim will also be needed for comparison (the same holds true for palm and bare footprints).
What should be photographed first?
The object should first be photographed as is, then photographed with the ruler. It is important that when doing one-to-one photography that the ruler is on the same plane as the object being photographed and the film plane is parallel to the ruler. This is why a level and a tripod are necessary.
Where are controls collected?
Control samples are acquired through any source that is considered completely reliable and whose identification has been verified through proper authorities. These sources include commercial vendors and manufacturers for such items as ammunition, fibers , and paints.
What is a standard reference sample and why is it important to collect?
Standard/reference samples (oral swabs from all victims) must be collected if a victim is not sure if collected evidence belongs to a suspect. These samples should be collected from all individuals who may be linked to the crime scene where DNA evidence is found or have come in physical contact with the item.
What is a reference sample in forensics quizlet?
Standard/ Reference Sample. Physical evidence whose origin is known such as blood or hair from a suspect, that can be compared to crime scene evidence.
Where is a standard sample generally taken from for comparison to unknown DNA samples?
These known samples are called reference samples. In some jurisdictions, a DNA sample is routinely taken from an arrestee during the process of booking and fingerprinting. However, this is an evolving area of law and states vary in their laws governing the collection of DNA from arrestees.