Unit 2 Forensic Science

What is the duty of a responding officer

They are responsible for controlling victims, suspects, law enforcement, and emergency medical technicians. They have to secure the border of the crime scene to prevent contamination of evidence, to prevent evidence from being damaged or taken, and to maintain the integrity of the scene.

Lead investigator

They manage the long-term investigation to solve the case such as, analyzing evidence, interviewing witnesses and suspects in depth, working with forensic experts, determine leads motives and potential suspects.

Rough sketch of a crime scene

Pencil drawn outline of the scene and location with markings where the fundamental evidence or objects are located in the crime scene.

Finished sketch of a crime scene

An accurately scaled sketch of the crime scene and its fundamental components and evidence.

Evidence

Matter produced before a court of law in an attempt to prove or disprove a point in issue, such as the statements of witnesses, documents, or material objects

Direct evidence

Directly proves a fact without requiring interference. Includes things like: Eyewitness testimony, video footage capturing the crime, confession

Indirect evidence (circumstantial evidence)

This type of evidence suggests a fact but requires reasoning or interference to reach a conclusion. It includes: Fingerprints at a crime scene (suggests presence but doesnt prove the act was committed), a person seen running from the scene of the crime, motive and opportunity to commit the crime

transient evidence

temporary evidence that disappears such as smoke, perfume, rain, temperature changes, wind or footprints melting in snow

physical evidence

indirect material evidence such as fingerprints, blood, saliva, weapons, glass, hair, fiber, tire tracks

trace evidence

physical evidence containing small quantities of materials such as gunshot residue, blood, carpet fibers, or pollen

demonstrative evidence

evidence that is created to present to jurors in court such as sketches, models, reenactments, photographs, or video

class evidence

cannot be attributed to a single source, object, or person, but can implicate a group of objects or people.

individual evidence

will point to a specific individual or object

According to the study, based on eyewitness confidence, how well can one predict whether or not the identification was correct? Assume the eyewitness is calm and not overly emotional.

If eyewitness confidence right after the crime is high, the identification is more likely to be correct.

If eyewitness confidence right after the crime is low, the identification is more likely to be correct.

If eyewitness confidence during the trial is high, the identification is more likely to be correct.

If eyewitness confidence during the trial is low, the identification is more likely to be correct.

If eyewitness confidence right after the crime is high, the identification is more likely to be correct.

bindle

hand folded envelope made from a piece of paper and used to store small pieces of evidence

case study

an in-depth examination of a particular event, individual, group, or situation to analyze key aspects, causes, effects, and outcomes

chain of custody

paper trail of every person that has been in contact with the evidence throughout its seizure, collection, preservation, analysis, and disposition

crime scene report

a written documentation of the crime scene

crime scene report

a written documentation of the crime scene

entry/exit log

record of all persons entering and leaving a crime scene including dates, times, and purposes

first responder

initial law enforcement agent arriving at a fresh crime scene

grid search

one parallel search is preformed followed by another parallel search at a 90 degree angle to the first so that a grid pattern is formed

parallel search

investigators form a line and walk parallel to each other, shoulder to shoulder, from one end of the crime scene to another

projection sketch

top view sketch of a crime scene similar to a floor plan

perspective sketch

three dimensional sketch of a crime scene drawn as the human eye views the scene with closer objects larger and farther objects drawn respectively smaller

standard reference sample

a known substance or control to which a piece of evidence is compared to look for similar characteristics

zone search

the crime scene is divided into four quadrants, and one investigator is assigned to each quadrant

What is the importance of following procedure when establishing boundaries around a crime scene?

It is crucial for preserving evidence, ensuring a thorough investigation, and upholding justice. Proper procedures help prevent contamination, wrongful convictions, or tampering of vital forensic evidence.

Why is it important for a crime scene report or chain of custody to be accurate?

Accuracy in crime scene reports and chain of custody directly impacts the justice system. Mistakes can lead to misinterpretation of evidence, wrongful convictions, or criminals going free. Proper documentation ensures evidence integrity, legal admissibility, and a fair trial for all parties involved.

Possible consequences of an improperly documented crime scene

• Misinterpretation of the crime scene can lead to wrongful accusations or failure to identify the real perpetrator.

• Contamination or loss of evidence may occur if it is not properly recorded or handled.

• Breaks in the chain of custody can raise doubts about evidence authenticity, making it unusable in court.

• Wrongful convictions or acquittals can result from missing or misleading information.