Criminalistics Final

What is a serum stain?

In blood analysis; transparent or yellowish; resulting from the liquid portion of blood (serum) that separates during coagulation

What is a mass disaster?

An unexpected event—natural or man-made—that causes widespread death, injury, or destruction, overwhelming local resources and emergency services

What are findings of strangulation?

Upturned neck, damage to hyoid bone, hemroging in eyes

What does blood do?

Physical evidence to identify individuals via DNA, help reconstruct scene, splatter tells direction

What is a shotgun entrance wound?

Ammo is firing pellets (BBs), many little holes increase as firing length increases

What about wounds show caliber?

You cannot determine caliber by the size of the wound

What is a loose contact wound?

No muzzle imprint, no powder stippling, soot/gun powder around wound

What does a distance wound look like?

Wound of entrance without surrounding residue, resulting from greater than 36” distance from gun

What is seen in an exit wound?

No skin defect, no rim of abrasion, no surrounding residue, can be any shape

What is blunt force trauma?

Most common variety of trauma, lethal or non-lethal, non-sharp, not a bullet; severity can depend on where, how, and with what

What are the different types of blunt force trauma?

Abrasions (scratches), contusions (bruises), lacerations (tear), fractures

What is a sharp force injury object?

Any object with a sharp or pointed edge: knives, scissors, screwdrivers, broken bottles/glass, golf clubs

What is a stab wound?

Stab wound is deeper than it is wide; incised wound is wider than it is deep

What will wounds tell you about sharp objects?

Wounds can be matched to the source, blade length, width, thickness, serrated or squared off, hilt guard, single or double edged

What are muzzle impressions?

An imprint on the skin from the muzzle of the gun, shows force, angle, and close distance characteristics

How does Rh factor affect pregnancies?

Rh factor is a protein on red blood cells; most people have it (are Rh-positive); an Rh-negative mother carrying an Rh-positive fetus, causes her immune system to produce antibodies that can attack the baby's red blood cells; can cause severe anemia, jaundice, heart failure, or stillbirth

What factors help in estimating time since death (oh Wow)

Environment, position of body, animals in the house, food on the stove, mail, stopped watches

What is different in the components of blood?

Plasma, red blood cells, white blood cells, and platelets

What is the survival time before death?

The duration between the initial fatal injury or event and the final cessation of vital functions; pronounced dead when the medic finds them

How can you differentiate lividity vs bruising

Cut the tissue; livor mortis-no discolor of the tissue. bruise-blood leaks into tissue

Blanching is..?

When you put force on the skin and it turns white, moves the blood away and then comes back; lasts for approximately 8–12 hours before the livor mortis becomes ‘fixed’

Lividity is?

The color of death; blood will pool in the lowest part of the body (gravity); turns the skin dark red/purple

How long after death will blood coagulate?

Within minutes, coagulation stops 20-30 minutes after death (blood will then remain fluid)

How do you estimate time of death?

Livor mortis, rigor mortis, algor mortis, eye potassium level, entomology (bugs), skeletonization

What is the window of death?

Estimated time range between a when the deceased was last seen or spoken to and the discovery of their remains, window of death doesn’t take into fact the event that cause the death

How do you take body temps?

Rectally or through the right abdominal quadrant into the liver; Algor mortis; body temp is a narrow range, not a fixed number; after death temp increases by 2 degrees in the first hour and loses 1.5-2 degrees per hour after that

What is algor mortis?

Temperature of the body after death; Newton’s law of cooling (rate of cooling is proportional to temp difference between object and surroundings)

What effects algor mortis?

Clothing slows loss of temperature, fat slows, child faster loss of temperature, wind faster, in water faster

What is Newton’s law of cooling?

Rate of cooling is proportional to temp difference between object and surroundings

Who can pronounce you dead?

Physician (can issue natural deaths), paramedics, and coroners or medical examiners (issue anything other than natural)

Can different stomach contents estimate time of death?

Yes, different meals/foods digest in different amounts of time; digestion stops once you die

How does victim’s blood transfer in shootings?

Splatter, transfer/contact, creates bloodstain patterns

Blood type question…

A blood has A antigens and anti-B antibodies, B has B antigens and anti-A antibodies, AB has AB antigens and neither antibody, O has neither antigen and both anti-A and anti-B antibodies;

Genetic question….

Uses DNA profiling and inherited genetic markers from biological evidence (blood, semen, hair) to identify individuals in legal, criminal, and civil cases

What is forensics?

The application of science to law; the are of finding whatever is left on a crime scene, developing it in such a way that it can be used to associated it with a person or people who were at the crime scene

How does blood spatter effect forensics?

Investigators can work directionally with blood spatter to reconstruct scenes

What enzyme is tested for when trying to detect blood?

Peroxidase or hemoglobin?

Who’s the daddy?

not sure

How do you process a crime scene?

Secure the scene, someone pronounced dead, gather evidence, body in body bag after all information is taken, notify next of kin, back to ME’s office

What is the medulla index?

The medulla is the middle part of a hair; the medulla index = (diameter of the medulla)/(diameter of hair); humans less than 1/3, animals greater than 1/2

What is a legal cause of death?

Gunshot wound, heart failure, dementia

What is ropyhnol?

Similar to diazepam, but 10x more potent; Valium; tasteless, odorless, dissolves in soda; feels like you’re drunk, no hangover; sedation in 10-20 minutes; date-rape drug

What is the fingerprint template?

Mathematical representation of a fingerprint's unique features; zeros and ones for faster processing

What can differenciate a man-made fiber?

Microscope; comparision or compound

What is a drug?

Substances of natural or synthetic origin which can alter the emotional state, perception, body functioning or behavior of an organism

What is low velocity blood spatter?

Bloodstain pattern resulting from a force or energy equivalent to gravitational pull; relatively large, passive stains, often

in diameter or larger

What is the formula for blood spatter analysis?

Angle of impact (alpha) = arcsin(width/length); A 90-degree impact creates a circular stain, while smaller angles create more elongated or elliptical stains.

What different things with blood stains explain?

Direction blood originated, angle blood struck surface, location/position of victim when wound was inflicted, movement of bleeding person, minimum number of blows

What is high velocity blood spatter?

pattern characterized by a fine mist of droplets, typically less than in 0.1mm diameter, created by high-speed impacts over 100 ft/s, such as gunshots

What laws do blood spatter follow?

Physics, mathematics (geometry and trigonometry)

Primer?

Chemical and/or device responsible for initiating the propellant combustion; LEAD, BARIUM, ANTIMONY; explodes on compression

Entrance wound?

Skin defect, rim of abrasion, surrounding residue, surrounding discoloration due to CO