Chpt 3 Flashcards
(25 cards)
Investigative team stages
Investigative stages, preliminary investigation, follow up investigation, and case preparation and prosecution,
Roles of investigation team
Dispatcher 911, Patrol Officer, first responding officers primary duties,
Call response
a questioning technique where an investigator asks a question (the call) and the suspect, witness, or informant provides an answer (the response), helping to gather information or detect inconsistencies.
Duties of first responding officers
- preservation of life, including their own
- Secure and preserve the scene and associated evidence
- Preserve the rights of all
Locards principle of exchange
whenever two things come into contact, they exchange traces of each other.
NASHU stand for
N - Nature of the crime
• A - Authority
• S - Suspect
• H - Happening
• U - Understanding
Transient evidence
Evidence that is easily lost or damaged
What is the Locard principle of exchange
Every contact leaves a trace
- What are 4 ways a corner is legally permitted to identify decedent?
Visual Identification – By family or friends who recognize the person.
2. Fingerprint Comparison – Matching fingerprints to records.
3. Dental Records – Comparing the person’s teeth to dental records.
4. DNA Testing – Comparing DNA to family members or existing records.
- Chain of custody
refers to the process of documenting and tracking the handling, transfer, and storage of evidence in a criminal investigation.
- Basic fingerprint ridge patterns
- Arches, friction ridges resembling rolling hills.
- Loops, well defined core or center with friction ridges of tightly would loops. Ulnar loops is the most prevalent.
- Whorls, Series of round friction from small to large
- Three types of fingerprints at crime scenes
Latent Fingerprints – Invisible prints left by oils or sweat on a surface.
2. Patent Fingerprints – Visible prints left on surfaces with substances like dirt or ink.
3. Plastic Fingerprints – 3D prints left in soft materials like clay or wax.
- IAFIS
Integrated automated fingerprint identification system
- CODIS
Combined dna index system
- Head stamp and what can it tell us
headstamp is the mark on the bottom of a bullet casing. It can tell us:
1. Manufacturer – Who made the ammunition.
2. Caliber – The size of the bullet.
3. Year – When the bullet was made.
This helps investigators figure out where the ammo came from and possibly link it to a suspect.
Primer strike and what can it tell us
A primer strike is the mark left on the primer of a bullet when a gun is fired.
What it can tell us:
1. Type of Gun – It can show which type of firearm was used.
2. How the Gun Was Fired – It can indicate if the gun was fired manually or automatically.
3. Link to a Specific Gun – It may help connect the bullet to a particular firearm.
Rifling
Rifling refers to the spiral grooves cut into the barrel of a firearm. These grooves cause the bullet to spin as it is fired, which helps stabilize the bullet and increase its accuracy.
What it can tell us:
1. Unique Marks – Rifling creates unique marks on the bullet, which can help link it to a specific firearm.
2. Type of Firearm – The pattern and characteristics of rifling can help identify the make and model of the gun used.
- NIBIN
NIBIN stands for National Integrated Ballistic Information Network. It is a system used by law enforcement to capture, store, and analyze ballistic evidence, such as bullet casings and firearm markings, to help link crimes and identify suspects.
- Blood pattern types
Passive Bloodstains – These are caused by gravity and include droplets, pools, and flows, usually from a wound or a moving person.
2. Transfer Bloodstains – Created when a bloody object (like a hand or weapon) comes in contact with a surface, leaving a pattern, such as a handprint.
3. Projected Bloodstains – Result from a force being applied to the blood, such as blood spattering from a gunshot or blunt force trauma.
- What cells do not have dna
White blood cells
- What are two types of firearms evidence: id,make,model, caliber and then ballistics
Firearm Identification:
• ID: Serial number of the gun.
• Make: Who made the gun.
• Model: The specific type of gun.
• Caliber: The size of the bullet it uses.
2. Ballistics:
• Examines marks left on bullets and cartridge casings to link a gun to a crime scene.
- What are three categories of firearms:
Rifles, handguns, long guns
types of velocity
Low Velocity – Blood drops falling from a height, like from a wound, usually creating larger droplets.
2. Medium Velocity – Blood patterns caused by blunt force, resulting in smaller, more distinct drops.
3. High Velocity – Blood mist or fine spray caused by high-impact forces like gunshots, creating tiny droplets.
