recognize, document, and collect evidence at the scene of a crime
list three goals of a crime scene investigator
when a person comes into contact with an object or another person, a cross-transfer of physical evidence can occur.
summarize locards exchange principle
hair, fingerprints, soil, blood, paint chips, glass
list at least 4 examples of materials that could be transferred form crime scene to a suspect
.hair, fingerprints, soil, blood, paint chips, glass
list at least 4 items of materials that could be transferred form a suspect to a crime scene
the intensity, duration,
and nature of the materials in contact determine the extent of the transfer.
More transfer would be noted if two individuals engaged in a fistfight than
if a person simply brushed past another person.
discuss how the intensity, duration and nature of the materials in contact can affect the extent of the transfer
firsthand observations such
as eyewitness accounts or police dashboard video cameras
discuss what is meant by direct evidence
indirect evidence that can be used to imply a
fact but that does not directly prove it
distinguish between direct and circumstantial evidence
Physical evidence includes impressions such as fingerprints, footprints, shoe prints, tire impressions, and tool marks. Physical evidence also includes fibers, weapons, bullets, and shell casings. Biological evidence includes body fluids, hair, plant part
distinguish between physical and biological circumstantial evidence
hair, fiber, glass, soil
identify four examples of trace evidence
.class evidence material that
connects an individual or
thing to a certain group individual evidence evidence that identifies a kind of particular person or thing
compare and contrast class evidence and individual evidence
.police, crime scene investigators, medical examiners, detectives, specialists
describe the types of professionals who are present at a crime scene
� Detectives look for leads by interviewing witnesses and talking to the
crime-scene investigators about the evidence.
� Specialists such as entomologists (insect biologists), forensic scientists,
and forensic psychologists may be consulted if the evidenc
describe the role d) detective e) other specialists
..� Police officers are usually the first to arrive at a crime scene. A district attorney may be present to determine whether a search warrant is necessary
for the crime-scene investigators.
� Crime-scene investigators document the crime scene in detail a
describe the role of each of the following people at a crime scene a)police officer b)crime scene investigator c) medical examiner
secure the scene, separate the witnesses, scan the scene, seeing the scene, sketching the scene, searching for evidence, securing and collecting evidence, chain of custody
summarize the main duties for each person involved in the seven steps of crime scene investigation 1 2 3 4 5 6 7
safety of individuals and preservation of evidence
explain the importance of securing the crime scene
Transfer, loss, or contamination of evidence can occur if the area is left unsecured
describe using specific examples how failing to secure the crime scene leads to contamination of the evidence
.This separation is done to avoid witnesses working together to create a story (collusion).
explain the importance of separating the witnesses at a crime scene
..The safety of all individuals in the area is the first priority.
Preservation of evidence is the second priority
discuss the first and second priority of the first responding officer
.Photos of the overall
area and close-up photos with and without a measuring ruler should be
taken. Triangulation of stationary objects should be included in the photos
as reference points. A view of the crime scene should be taken from several
different
elaborate on the idea of "seeing the scene" include in your answer what type of photos needs to be taken of the crime scene and the importance of a ruler being placed in the photo
.. All objects should be measured
from two immovable landmarks. On the sketch, north should be labeled
and a scale of distance should be provided. Any other objects in the vicinity
of the crime scene should be included in the sketch. This includes doors,
explain how a rough sketch of the crime scene is drawn. include in your answer a)how to use at least 2 immovable landmarks when measuring any objects b)how direction should be indicated on the sketch c)the role of a scale of distanced)what other objects should be included in the rough sketch e)what other info should be written on the sketch
.� When did the crime occur?
� Who called in the crime?
� Who is the victim?
� Can the perpetrator be identified?
� What did you see happen?
� Where were you when you observed the crime scene?
list several question that an investigator might ask a witness to a crime
.labs and reconstructing crime scene
discuss the role of technology in documenting a crime scene
.primary crime scene-where the crime took place, the location
secondary crime scene-other than the primary crime, a location scene, but that is in some way
related to the crime, where
evidence is found
distinguish between a primary and a secondary crime scene
.
describe each of the various search patters spiral grid, linear, quadrant
.All evidence needs to be properly packaged, sealed, and labeled. Case number
� Item inventory number
26 Crime-Scene Investigation and Evidence Collection
11/30/07 11:33:24 AM � Description of the evidence
� Name of suspect
� Name of victim
� Date and tim
demonstrate proper technique in collecting and packaging trace evidence
.. Liquids and arson remains are stored in airtight, unbreakable containers. Moist biological evidence is stored in breathable containers so the
evidence can dry out, reducing the chance of mold contamination. After the
evidence is allowed to air dry, it
compare and contrast the methods of collecting and packaging 1. liquids and arson remains 2. moist biological evidence 3. dry evidence
.1. Choose the appropriate-size sheet of clean paper for the bindle.
2. Crease the paper as shown in the figure.
3. Place evidence in the X location.
4. Fold left and right sides in.
5. Fold in top and bottom.
6. Insert the top flap into the bottom flap t
describe how to form and package a paper bindle
.� Case number
� Item inventory number
� Description of the evidence
� Name of suspect
� Name of victim
� Date and time of recovery
� Signature of person recovering the evidence
� Signature of any witnesses present during collection
list the items that must appear on an evidence log
This process ensures that the evidence has been responsibly handled as it was passed from the crime scene to a courtroom
explain the importance of the chain of custody of evidence
That person takes it to the lab and signs it over to a technician, who opens the package for examination at a location other than the sealed edge. On completion of the examination, the technician repackages the evidence with its
original packaging, reseal
describe how the evidence bag is opened and resealed as diff technicians examine the evidence
.A forensic lab processes all of the evidence the crime-scene investigation collected to determine the facts of the case
describe how evidence from a crime scene is analyzed
Unlike what television CSI programs portray, forensic lab technicians are specialized and process one type of evidence.
contrast the evidence examiners on television programs such as CSI with real life evidence examiners
.Crime-scene reconstruction involves forming a hypothesis of the sequence of events from before the crime was committed through its commission. The evidence is examined and compared with the witnesses' statements to determine the reliability of their acco
describe how a detective will try to reconstruct a crime scene using the documented evidence and any eyewitness accounts of the crime
Requirements of a Forensic Investigator
must be able to identify the evidence, record it, and determine its significance. collect all evidence.
How to be a good observer
examine our environment systematically, consciously decide to observe everything, gathering information, write down and photograph
Physical Evidence
any and all objects that can establish that a crime has been committed or can provide a link between a crime and its victim or a crime and its perpetrator
First responders
police officers who discover and secure the crime scene. First priority is the safety of all individuals. Assist or preserve the life of the victim.
Crime scene investigators
document crime scene and collect evidence. assess the extent of the crime scene. includes lead investigator, photographer, sketch artist, evidence collector, evidence custodian. must disturb things as little as possible. particular attention should be paid to the floor.
Medical examiners
may be necessary to determine cause of death
Detectives
interview witnesses and share information with crime scene investigators
Photography
overall photos of the scene are taken before evidence is recovered, from several different angles, object must not be moved until they have been photographed, close ups should be taken, a ruler or other measuring scale should be inserted, photo log, digital camera photos cannot be used as evidence in court
Crime Scene search patterns
spiral (conducted by a single searcher), grid (search strip along one axis, then search the same area on a perpendicular axis), strip or line (indoor or large or open areas, personnel line up shoulder to shoulder arms length), quadrant or zone (area is divided into zones, each person is assigned a zone, group of investigators),
Direct Evidence
first hand observations: eye witness accounts, police dashboard video cameras, confessions
Circumstantial Evidence
indirect evidence that can be used to imply a fact but does not directly prove it (physical and biological)
recognized, selectively collected, preserved properly
Evidence must be
Protective gear
latex gloves, shoe covers, overalls, mask/goggles, biohazard bag for infectious and blood-soaking objects
Preservation
properly packaged, sealed, and labeled. kept in separate containers. liquids, charred debris, stored in airtight unbreakable containers. biological evidence in a paper bindle or druggist fold.
Collected and sent to forensic laboratory
victim's clothing, fingernail scrapings, head and pubic hairs, blood, vaginal/anal/and oral swabs (sex-related crimes), recovered bullets from the body, hand swabs from shooting victims.
Reference sample
from a suspect or victim that can be compared to crime-scene evidence
Chain of Custody
record of all of the individuals who maintained unbroken control over the items of evidence. single most important piece of paper generated at the crime scene. established that the evidence collected is the evidence being presented in court
Forensic Pathology
examination of body through autopsy to determine cause of death
Forensic Entomology
study of insects and their relation to a criminal investigation, commonly used to estimate the time of death. Blowfly first on crime scene.
class evidence
material that connects an individual or thing to a certain group
crime-scene reconstruction
a hypothesis of the sequence of events from before the crime was committed through its commission
individual evidence
a kind of evidence that identifies a particular person or thing. Eyewitness accounts or a police dashboard video camera.
paper bindle
a folded paper used to hold trace evidence
primary crime scene
the location where the crime took place
secondary crime scene
a location other than the primary crime scene, but that is in some way related to the crime, where evidence is found
trace evidence
small but measurable amounts of physical or biological materials found at a crime scene