forensic science

What happened in Frye v. United States? What impact did this have on forensic science?

James Frye was on trial for murder. They attempted to prove his innocence with a new machine; the judge decided the machine had no "general acceptance." This ruling established that there must be general acceptance from experts on methods and principles.

What are the sections recognized by AAFS (American Academy of Forensic Sciences)?

Criminalistics: physical evidence found in a crime scene

Digital and multimedia sciences: digital and multimedia evidence, computer evidence

Engineering science: variety of scientific and engineering evidence

General: study evidence and investigate crimes

Jurisprudence: study legal aspects of forensic science

Odontology: study teeth, identify people based on dentition

Pathology/Biology: study of cause and manner of death, often medical examiners and perform medicolegal autopsies

Physical Anthropology: study skeletal human remains.

Psychiatric Behavioral Science: evaluate mental health involved in illegal proceedings

Question documents: analyze documents that have been altered

Toxicology: Analyze biological samples to detect drugs, alcohol, and other chemicals and poisons

What is the role of the First Officer to arrive at a crime scene?

Get medical assistance if needed, take statements from anyone currently on the crime scene to see if there are any witnesses (detain them if there are), seal off boundary and post officers to exclude civilians, wait for backup and call for forensic investigators or any additional officers. Preserve evidence.

Draw the shape you would expect a blood drop to be if it landed on the surface at a 90 degree angle.

Circle

Draw (and label) the blood drop if it landed at 90 degrees on a rougher surface.

circular but with small spines (tail- elongation of drop —> spine —> satellite)

Draw the shape you would expect it to be if it hit at 60 degrees and 30 degrees.

60: slight oval shape, like a small head. 30: thin oval, like a teardrop

Draw a blood droplet that hits a surface at a 30 degree angle, traveling from right to left.

thin oval but its sideways

List the several types of crime scene search strategies. In one sentence for each, describe when you would use each strategy.

Lane or Search: Good for large outdoor areas

Grid Search: More thorough than lane but takes twice as long, good for if you have more time

Zone Search: Good for indoor spaces

Spiral Search: Outdoors, where boundaries are unclear

What are the 3 main ways a crime scene must be documented? For each, write out the minimum requirements and best practices.

Photography: Overall, Mid-range, closeup before and after altercation. Never delete a photo.

Sketch: only relevant info, Projection ( usually bird's eye), perspective (more 3D, naked eye POV), Schematic (sequence of events), Make sure it's detailed, include small areas not focused in overall drawing.

Notetaking: The identity of the person who contacted the investigator, Time of contact and arrival at the crime scene, Preliminary case information, Personnel present on arrival and those being contacted, all observations made by the investigator, and the time observations were made

What is the purpose of a crime scene search?

Answers who, what, where, when, and how questions. The evidence can (dis)prove suspects and/or testimony. Also, bridges the gap between probable cause and beyond a reasonable doubt.

Which 3 views should be shown in photographs of a crime scene?

close up, mid range, and overall

List what must be included in a crime scene sketch.

Case identifier/ Date, time, location/ Boundaries of scene (outline)/ Location of objects and evidence/ Dimensions of room, furniture, doors, and windows/ Measurements of objects, evidence, furniture, doors, windows, entrances and exits, bodies, people/ Take measurements from fixed location like wall or curb/ May need to take vertical measurements as well/ Weather and lighting conditions/ Arrow pointing north

Describe what collecting a standard reference sample means at a crime scene.

physical evidence whose origin is known, like blood or hair from a suspect, that can be compared to crime-scene evidence

What are some possible carriers of trace evidence that investigators should collect if possible?

Clothing, sheets, carpet

What can be used to make an identification of a deceased individual?

Fingerprints

Blood/DNA sample

Autopsy

What are the different manners of death? Describe the difference between cause of death and manner of death.

natural, suicide, homicide, accidental, and undetermined.

The cause of death is what initiates the series of events ending in death.

Manner of death is the circumstances that led to the death.

What are the 3 different parts of autolysis?

Algor mortis: the cooling of the body after death

Livor mortis: the pooling of blood in body due to gravity and lack of blood circulation (areas touching the ground like calves and butt will not have any pooling)

Rigor mortis: muscle stiffening

What are the 3 main types of bloodstain patterns?

Passive stains: typically result from gravity acting on an injured body (drops, flows, pools, clots)

Transfer stains: objects coming into contact with existing bloodstains and leaving wipes, swipes, or pattern transfers behind

Impact stains: occurs when an object impacts a source of blood (like a hammer hitting a head)

Describe the different types of projected blood stains (spatter patterns)

Forward Spatter: projected outward and away from the source (towards direction of bullet)

Back Spatter: projected backward from the source (not towards direction of bullet)

Cast-Off: when a blood-covered object flings blood in an arc onto a nearby surface.

Low Velocity Spatter: drops with diameters of 4 mm or more normally produced by an applied force of up to 5 ft/sec, caused by blunt objects or dripping

Medium Velocity Spatter: Drops with diameters of 1-4 mm with an applied force of 5 to 25 ft/sec, can be produced by beatings, typical of a blunt instrument swung by hand

High Velocity: drops with diameters less than 1 mm from an applied force of 100 ft/sec or faster, produced by gunshot or high speed machinery

What is the role of an expert witness? How is it different from that of a lay witness?

The role of an expert witness is to provide facts, impressions, opinions, and/or conclusions when testifying in court. A lay witness can only provide facts and impressions during their testimony. Since the expert witness' testimony comes from a more knowledgeable individual, they are permitted to offer opinions and conclusions about evidence.

Describe the relevance of the fourth and fifth amendment for forensic science.

Fourth Amendment: prohibits unreasonable search and seizure

Fifth Amendment: states cannot be compelled to self-incriminate

What is the difference between a coroner and a medical examiner?

Coroner observes the body for causes of death and things like wounds or bruises. Not physicians.

Medical examiner goes more into depth by doing internal exams of the body and calculating things like time of death. Have medical education and training.

What effect does the porosity and/or smoothness of a surface have on the shape of blood spatter?

Porosity and smoothness of a surface dictates the satellites, spines, elongation tails of a blood spatter. Depending on the surface, droplets could be more circular round while others can be more elongated.

What is eugenics? Who coined the term?

practice or advocacy of controlled selective breeding of human populations to improve the population's genetic composition

Coined by Francis Galton

What types of wounds are commonly found when someone is defending themselves from an attacker?

Defensive Wounds: outer forearm & lower extremities wounds (bruises, scrapes..)

What is chain of custody? How is it maintained? Why is it important?

paper trail of the ownership/movement of evidence. It is maintained by giving evidence-specific barcode numbers and packaging, and having a log of records of people who had the evidence. This is done to ensure that there is little tampering with evidence.

What are the most important court cases relating to forensic science?

Brady v. Maryland (1963) "The Brady Rule"

Kumho Tire v. Carmichael (1999)

General Electric v. Joiner (1997)

What is Locard's Exchange Principles? Who is Locard? How is this relevant to forensic science?

Locard is a French criminologist. Exchange principle discusses that when objects come in contact, materials are exchanged. Forms the principle of trace evidence. It also emphasizes the preservation of physical evidence from a crime scene.

What is the definition of forensic science?

The application of science to the criminal and civil laws that are enforced by police agencies in a criminal justice system (saferstein and roy)

The use of scientific methods or expertise to investigate crimes or examine evidence that might be presented in a court of law (NIST, 2013)

What rules does scientific evidence have to meet that are different than other types of evidence? Why is it so important to follow these rules?

Given by people qualified as experts, so it can have an aura of truth, which necessitates ensuring the evidence is valid and reliable.

What happened in Daubert v. Merrell-Dow? How did this influence forensic science?

Daubert sues MD for birth defects she claimed occurred from Bendectin (used to treat nausea in pregnant people)

Statisticians on either side disagree with each other about the conclusions of their studies

MD argues that Daubert's statistician did not use methods that were "generally accepted" by scientific community, so it failed to meet Frye Standard

Court agreed, but said they must use Federal Rules of Evidence (FRE 702)

Judge must act as "gatekeeper" who decides when scientific evidence is admissible and suggested: Falsifiability, Knowledge of error rates, Peer review, General acceptance

Mandated scientific techniques must be based on demonstrable scientific principles