ETX 020 Midterm 1

What is an example of Forensic Science?

The application of science for the purposes of the law. The application of science to evidential items in a crime laboratory. Using science to settle a legal argument.

The murder of Penny Parker was a cold case that was solved using which forensic method?

DNA typing

In the Penny Parker case, there was strong evidence to suggest Mr. Jenning was a suspect through relationship DNA testing. This was true because the DNA typing results from the semen stain was consistent with his:

Daughter

Which of the following is not a duty of a Criminalist?

Interview the suspect.

A Forensic Toxicologist specializes in analyzing ________

Blood, urine, and tissue for drugs and narcotics.

A bag of unknown powder was collected from a clandestine lab. Criminalist Walter W. had taken the powder for analysis. Which instrument can be used to identify the substance?

Gas Chromatography-Mass Spectrometry (GC-MS)

Which of the following is not a duty of a firearms analyst?

Analyze the firearm for DNA and upload the profile results to CODIS.

Which of the following best describe criminalistics?

The science of individualization.

What is the "Key" to forensic science?

The forensic association and the significance of the association.

The Locard Exchange Principle states:

Every contact leaves a trace.

What is the significance of the "forensic science diamond"?

It can be used as a model to help forensic scientists make an association.

An older male was a victim of a robbery at his house. The victim proposed the suspect had gotten inside through the back window. The evidence technician discovered a shoe print, cigarette butt, and a drop of blood the size of a needle tip by the window. A suspect was found hiding in the trashcan across the street. Assuming modern forensic analytical methods, which of the following evidence could associate the suspect to the crime scene?

Cigarette butt, drop of blood, and shoe print.

Define cause of death.

The disease or injury responsible for the lethal sequence of death.

Define manner of death.

It explains how the cause of death arose, natural accidental, homicide, suicide, or undetermined.

A deceased woman was found with multiple stab wounds. The autopsy report showed the presence of heroin in the woman's body. The forensic pathologist noted in the report that the woman was murdered, and the stab wounds lead to her death. What is the manner and cause of death in this situation, respectively?

Homicide and stab wounds.

Why are rigor mortis and algor mortis poor indicators of time since death?

Temperature can affect the rate of rigor and algor mortis and the person's clothing can affect the rate of rigor and algor mortis.

Explain how livor mortis is useful in homicide investigations.

It can indicate if a body has been repositioned after death.

Explain how stomach content analysis is useful in homicide investigations.

It can be used to estimate the time of death.

What is the difference between autolysis and putrefaction?

Autolysis is the breakdown of protein by the body's digestive enzymes while putrefaction is done by bacterial and fungal activity.

Why is it important not to reintroduce evidence into a crime scene in order to take photographs?

The evidence loses its value, the evidence may not be placed at the exact spot as it was found, and the photographs would not be accurate.

How can you tell if a body has been relocated after death?

By observing the area where the blood on the body pooled and coagulated.

Why is it important to obtain a copy of the 911 call?

The person who had called could be the suspect, it can be used as evidence in court, and it can be used to corroborate the caller's alibi.

Once a dead body has been found, who has the legal jurisdiction of the victim?

Medical Examiner/Coroner

What do all sketching techniques have in common?

They all include evidence, all sketching techniques have a point of origin, and they are normally "not drawn to scale."

An infant was found dead inside a dumpster. The body was so decomposed that the pathologist could not determine how the infant may had died. However, there was some evidence to suggest the parents of the infant were involved, but not enough to convince the judge/jurors. What would the pathologist conclude as the manner of death?

Undetermined

Several forensic techniques were demonstrated in the Yosemite Murder Case. Which of the following was mentioned?

Stomach contents analysis

How were the victims in the rental car identified in the Yosemite Murder Case?

A camera was found by the rental car that contained photos of the victims.

What evidence found in the suspect's bag associated the suspect to the victim at the little green cabin in the Yosemite Murder Case?

The duct tape on the victim matched the ends of the duct tape in his bag.

Which of the following is an example of known evidence?

Blood sample drawn from a suspect.

A DNA analyst would like to perform a presumptive test on a red stain from a shirt. The analyst thinks the stain is blood, so a Kastle-Meyer test for human blood is common. To perform the test, the analyst requires a positive control. What can be used as a positive control in this scenario?

The analyst should use human blood from a known source.

Which of the following would be an example of a false positive?

A blood test result for human blood on a known red food coloring was positive.

Which of the following would be an example of a false negative?

A drug test result from a daily drug user was negative.

What is a negative control?

It is used to determine if a chemical test is working properly and it is a sample that is supposed to give a negative result.

The Trier-of-fact in court are the ____

Judge and Jury.

Detective Hopkins discovered a small colored chip on a pole from a hit and run. By analyzing the chip, he determined the chip was automotive paint. What would you classify this evidence as?

Identity

Which of the following could affect the transfer of evidence?

The pressured applied during contact, the form of evidence, and the number of contacts.

Which of the following could be used as evidence in court?

Personal testimony, language of documents, and material documents.

Civil Court

A court dealing with noncriminal cases. 51% or more standard of proof.

Criminal court

A court that has jurisdiction to try and punish offenders against criminal law. 90% or more standard of proof.

The Penny Parker Case

Forensic Technique Used: DNA Typing

How was it solved? running semen of assaulter in the database, match was found with the daugther of the criminal.

What qualifies an individual as an Expert Witness?

They need to have studied and done work in that area.

What are the educational requirements to work in a crime lab?

A bachelor of science degree in some form of science (bio, chem, etc).

What are the educational requirements to work as a DNA analyst?

A bachelor of science degree in some form of science but needed to take specific biology courses related to DNA.

What is the key to forensic science?

The associations and the significance of the associations.

What is Locard's principle?

Every contact leaves a trace.

What is the forensic diamond?

A visual representation of the connection that exist between victim, suspect, evidence, and crime scene.

What types of evidence can be used to make a forensic association?

Blood, fibers, paint chips, glass, soil, fingerprints, hair, biological material.

What is manner of death?

The circumstances that result in death, which are designated as natural or unnatural.

What is cause of death?

Lethal sequence of events that leads to death.

What is rigor mortis?

The stiffening of the body after death.

What is livor mortis?

Settling of blood.

What is algor mortis?

The cooling of the body after death.

What is the order of shut down after death?

1. Respiratory System

2. Circulatory System

3. Central Nervous System

4. Cellular Pathway

Where does decomposition start?

Decomposition starts on the inside of the body.

Why is stomach content important?

It can be used to estimate the time of death, the heavier the last meal, the longer it'll stay in the stomach.

What is vitreous potassium?

Intracellular fluid in the eye. Works as a built in clock to project time of death. Depends on the location.

What is autolysis?

Auto=self, lysis=destruction: Self-destruction of cells by their own lysomal digestive enzymes after death or in a pathological process.

What is putrefaction?

The process of decay or rotting in a body or other organic matter (tissue).

What are other markers we can use to estimate time of death?

Environment, habitats, daily activities, and microbiome.

What conditions affect transfer?

Pressure applied during contact, the number of contacts, how easily the item transfers material, the form of evidence, and how much of the item is involved in the crime scene.

What is real evidence?

Real Evidence is Physical evidence, like a hard disk drive.

What is demonstrated evidence?

Created later to augment/explain real evidence.

What is persistence?

The length of time trace evidence will remain on an item following a transfer event.

Indentity

Defines object in a group.

Classification

Organizing the object into a more specific group.

Individualization

Demonstrating that the sample is unique, even among members of the same class

What is positive control?

A positive control is a test using a substance known to produce a positive result. Testing the positive control allows you to see how to visualize a positive result and ensures that the reagents and protocols are working properly

Type 1 error

False positive

Type 2 error

False negative

Importance of blood pattern analysis

BPA suggests a story, sequence of events. Reconstruction of crime scene

Why do we do BPA?

It can help investigators reconstruct a crime scene and answer key questions about what happened.

What are the main classes of bloodstains?

Passive, transfer, and projected or impact stains.

What are the four premises which are the basis for significant forensic associations?

Victim, evidence, crime scene, and suspect.

Passive bloodstain

A bloodstain formed primarily by the action of gravity alone.

Spattered bloodstain

Impact, secondary, or projected mechanism.

Altered bloodstain

A bloodstain or pattern with characteristics that indicate a physical change has occurred.

Wipe stain

A stain created when an object moves through a pre-existing bloodstain.

Skeletonized stain

A bloodstain that has been altered after a period of drying, leaving observable peripheral characteristics of the original stain

Swipe stain

Transfer of blood onto a target by a moving object that is itself bloodstained

Voids

The absence of blood in an otherwise continuous bloodstain pattern that suggests the presence of an intermediate target that may have been removed.