Forensic Science

A suspect is linked to a murder by the presence of hair found on a chair at the victims' house and a fingerprint found on the coffee table. Crime-scene investigators found a fingerprint consistent with a suspect's fingerprint, and they found the hair to be similar to the hair from the head of the same suspect. Provide arguments that this evidence is not sufficient to prove the suspect was the murderer. Include the following terms in your answer

- Circumstantial evidence- fingerprint, Foot prints, Hair, - Class evidence- Hair - Individual evidence- Fingerprints - Direct evidence- Fingerprint but not the best

what are the different kinds of search patterns? and when are they used?

- Outdoors/triangular, square, rectangular - Lane or line, Spiral or circle, Pie or wheel, grid, Zone or quadrant - the size depends on the size of the search and how many detectives there are

explain how the chain of custody should work

1. The individual who finds evidence, bags the evidence in a plastic or paper container. 2.The final container for the evidence is a collection bag or box, which is labeled with pertinent information. 3.The container is then sealed and the collector's signature is written across the seales edge. 4.The container is given to the next person. 5.That person takes it to the lab and signs it over to a technician who opens the package at a location other than the sealed edge. 6.On completion of the examination, the technician repackages the evidence in its original packaging, inserts and reseals the evidence in new packaging, and signs the chain-of-custody log attached to the packaging. 7.This process ensures tracking of the evidence as it passes from the crime scene to a courtroom.

how should evidence be collected?

A paper bindle is good for small dry Trace evidence. Wet evidence should be placed in a paper container and sealed to let it air dry.

securing and collecting evidence

all evidence needs to be properly packaged, sealed, and labeled - specific procedures and techniques must be followed

what is a first responder? what is their job/role?

an officer that keeps a security log of all who visit the crime scene and secures the scene

what are the three most common kinds of staged crime scenes?

arson, burglary, murder staged like suicide

At the scene of the crime, the evidence collector found a damp, bloody shirt. The evidence collector quickly wrapped the shirt in a paper bindle. He inserted the paper bindle with the shirt into an evidence bag. The bag was sealed with tape, and the collector wrote his name across the tape. The CSI also picked up three cigarette butts and put them into a plastic evidence bag, which he sealed and labeled. An evidence collection log was completed and taped to each of the evidence bags. What did he do incorrectly?

cigarette butts should be in a paper bindle so it can be breathable

what is an evidence log?

document that is attached to the evidence container

what is direct evidence?

first-hand observations ex: video, receipt, eyewitness, confession

what is the secondary crime scene?

if the crime scene was moved to a new location

what is biological circumstantial evidence?

includes DNA, bodily fluids, hair, plants, pollen, natural fibers

what is physical circumstantial evidence?

includes footprints, fingerprints, shoe prints, glass, soil, fibers, weapons, bullets, shell casings

Define crime-scene reconstruction

involves forming a hypothesis of the sequence of events from before the crime was committed through its commission ex: blood spatter interpretation, rebuilding the ramseys house

what is collusion?

is when witnesses from a crime scene get together and discuss what happened and agree to tell the story different from what really happened

Describe the role of the paper bindle. when is it used? what is another name for the paper bindle?

it is an ideal packaging for small and dry evidence the size depends on the size the evidence wet evidence: paper container that is breathable so it does not start to mold (no plastic) druggist fold

What is circumstantial evidence?

it is indirect evidence that can be used to imply a fact but that does not prove it. evidence that establishes a motive ex: the pen that wrote the note in JonBenet case, the flashlight could've been the weapon but it cannot be proven

what is class evidence?

material that connects a group of people to a crime scene ex: found a piece of evidence on something and it's sold at a store/blood type

what is triangulation?

mathematical method of calculating the location of an object from the locations of other objects

what is individual evidence?

narrows an identity to a single person or thing ex: fingerprint, DNA, or hair follicle

seeing the scene

the crime-scene examiner needs to see the scene/photos of the overall area AND close-up photos with and without a measuring ruler should be taken

Atlanta Child Murders What type of circumstantial evidence linked Wayne Williams to the crimes?

Green nylon fiber and the carpet fiber in the car He was seen close to where the body was

Analyze the JonBenet Ramsey case described in the beginning of the chapter and from topics we have discussed in class Describe how the father's actions upon finding the body resulted in a loss of evidence and/or contamination of the evidence.

He moved the body from the basement when he took her upstairs. He also put her on the ground instead of a couch. She was actually moved several times. There had been several people in the house walking around so this contaminated evidence.

what is Locard's principle? how does it work and what does it imply?

Locard's principle holds that the perpetrator of a crime will bring something into the crime and take something out of the crime scene with them. It implies that there is always evidence but it is up to humans to find and use the evidence correctly. Transferred: You come in direct contact. Or you have fibers after direct contact and then go and someone has direct contact with you

Atlanta Child Murders Describe the direct evidence linking Wayne Williams to the crimes.

They found the carpet fibers on the victim that was were found in his home

Analyze the JonBenet Ramsey case described in the beginning of the chapter and from topics we have discussed in class The crime-scene investigators who first arrived at the scene had a preconceived idea that JonBenet was kidnapped. Describe how important evidence may have been lost or destroyed because they assumed they were investigating a kidnapping as opposed to a murder.

Since they assumed it was a kidnapping they didn't not secure the house. This means that stuff could have been moved, numerous prints were added, and stuff was not left where it originally was.

Discuss true crime scenes with that of faked/staged crime scenes.

The perpetrator stages a fire to cover some other cirme such as murder ro burglary. Burglary can be staged to collect insurance money. Murder staged to look like sudicide. The death may be caused by alcohol or drug overdose or it may be caused by violence. Consider the following to determine if a crime scene is staged Initially treat all death investigations as homicides. Are the wounds on the victim consistent with the suspected weapon employed. Could the wounds be easily self inflicted. Establish a profile of the victim. Evaluate behavior. _________________________________ Evidence doesn't lie. Doesn't match up witnesses and their testimony

sketching the scene

a crime scene investigator eventually makes an accurate sketch of the crime scene, noting the position of the remains and any other evidence/all objects are measured from two immovable landmarks-all objects within the vicinity of the crime scene should be drawn, labeled, and accurately included

what is a crime scene investigation?

a multidisciplinary approach in which scientific and legal professionals work together to solve a crime

what is trace evidence?

hair, skin cells, clothing fibers, pollen, glass fragments, debris from a person's clothes, makeup, or any number of different types of material can be transferred from one person or object to another

A dead body and a gun were found in a small room. The room was empty except for a small desk and a chair. The room had two windows, a closet, and a door leading into a hallway. The crime-scene sketch artist measured the perimeter of the room and drew the walls to scale. He sketched the approximate position of the dead body and the gun. He sketched the approximate location of the chair and the desk. What did he forget to do?

he forgot to draw the windows and the door. He didn't label anything and he forgot to measure and forgot the frame of reference (datum point)

define a datum point

permanent, fixed points of reference which allows measurements and directions to be established ex: corner of a building, trees, and/or house

What are the major goals of crime scene investigation?

recognize, document, photograph, and collect evidence at the scene of the crime

the 7 S's of crime investigation

securing the scene, separating the witnesses, scanning the scene, seeing the scene, sketching the scene, searching the scene, and securing and collecting the evidence

After obtaining evidence, a lab technician removed the tape that contained the signature of the crime-scene evidence collector. Upon completion of her examination of the evidence, the lab technician put the evidence back into a paper bindle and inserted the bindle into an evidence bag. The technician resealed the bag in the same place as the original crime-scene investigator. After carefully sealing the bag, the lab technician signed her name across the tape. She completed the chain-of-custody form on the outside of the evidence bag and brought the evidence to the next lab technician at the crime lab.

should have opened it up in a different area and sign in a different place, she broke the original seal and evidence and put her name on it

What is chain of custody?

signature part ~ list of people that have been in contact with evidence

why is it important to separate witnesses at the crime scene?

so they do not work together to create a story

scanning the scene

the forensic crime-scene examiners first need to scan the scene to determine where photos should be taken

what is the primary crime scene?

the location where the crime occurred

securing the scene

the officer protects the crime scene and restricts all unauthorized persons from entering

searching the scene

the type of patterns depends on the size of the area being searched and the number of the investigators (single ~ gridded, linear, or spiral pattern) (group ~ linear, zone, or quadrant pattern)

what role do specialists play in crime scene investigators?

they focus on one specific piece of evidence ex: blood, bullets, hair, reconstruction, fingerprints

separating the witnesses

witnesses must not be allowed to talk to each other so that they don't work together and create a story