485 Forensic Law Midterm Exam
The most important fact that makes forensic evidence circumstantial is because science cannot be clearly defined by law. The legal system have created standards and written legal rules regarding the admissibility of forensic evidence. When forensic evidence that is presented in court is rarely unaccompanied by an expert witness to provide the court room with a professional explanation backing the reliability of the forensic process used to collect the relevant evidence. This is one the major obstacles in the modern courtroom.
Expert witnesses are intended to provide the court with a detailed description of the forensic evidence being presented and how that evidence was analyzed through the use of forensic science. This makes an expert witness’s testimony a testimony to probability and circumstance, rather than actual fact. Consequently, the forensic evidence that is presented is ruled as circumstantial. The primary reason that science cannot be clearly defined by law is the rate of change and new theory that occurs regularly in science.
There have been numerous cases where scientific evidence is found to be incorrect or inconclusive when it is admitted into evidence. This is a major concern for the courtroom as false convictions are detrimental to the integrity of the judicial system. Admissible forensic evidence is most always considered circumstantial so that there must be other forms of evidence to support the conclusion made from the forensic evidence to make a ruling. 2. Explain ways in which an opposing attorney can challenge an expert’s testimony in court.
The primary goal of an attorney during cross examination is to destroy the credibility of a witness’s testimony. Expert witnesses are held to a different standard during trial and are considered professional witnesses as they speak on the behalf of a professional opinion and understanding of the information being presented; rather than the account or an experience. Regardless of who they witness is, it is important the Federal Rules of Evidence are upheld during cross examination. There are multiple rules against the presentation of past history of witness and attack of their personal character.
That being said, an attorney may reference background and qualifications of an expert witness disprove the creditably of the witness as a professional in the field they are giving testimony to. An attorney may do this by researching the expert or the field that they practice and present them question that may cause they to refute their previous testimony or have no answer to a question. Causing an expert witness to look confused or untruthful on the stand shows the jury that jury that their testimony may not be credible or the judge has the authority to dismiss the witness completely.
Another approach that is commonly executed during cross examination by an attorney is challenging of the validity and probativity of the expert witnesses testimony. Attorneys may focus on the limitations of the testimony and attempt to show the jury that the testimony is insignificant and inconclusive to show any benefit in proving or disproving any evidence or a fact at trial. An attorney may also challenge the purpose of the testimony. If the attorney can ask questions that show the testimony is insignificant and is not being used to prove or disprove evidence.
Then the attorney may be able to have the judge dismiss the testimony. 3. Explain exactly what makes a witness an expert witness and provide an example of a specific forensic science expert witness. Also, explain what scientific expert opinion is and what is required before a court will allow this type of special testimony. An expert witness is considered an expert according to their credentials in the professional field that they are testifying in accordance with. Expert witnesses are used by attorneys to give professional opinion and explanation of information that the common individual would otherwise have no understanding of.
Searching the web I discovered SEAK a website devoted to compiling information on expert witness. All of the expert witnesses listed on the site have been previously used in cases to provide testimony to specific evidence that is within the parameters of their expertise and professional credentials. Jill Kessler Miller is a great example of a specific expert witness. Jill resides in Southern California and is an expert in forensic science and dogs. She has testified in nine trials over the past four years. She has had over twenty-five years of experience with training dogs.
She has a college degree in English and a graduate certification in Animal Policy & Advocacy. The site also lists the multiple specific topics she gives testimony to. This is a great example of an expert witness because she lists are her professional credentials and specific fields that she will testify about in court. Dog bites and veterinary forensics are her direct links to forensic evidence. An expert witness’s expertise, training and special knowledge of a subject allows them to be give opinion is court. There is an exception to the rule against witnesses presenting anything but fact.
Regardless, an expert witness’s opinion must be unbiased and bases solely on their special knowledge, train, and expertise in the field. The opposing attorney also has the right to confrontation to this opinion. 4. Explain in general how forensic evidence and analysis of this evidence can aid investigators in determining what took place at a crime scene. How would this information be helpful to an investigation? There are multiple different disciplines of forensic evidence and each different of discipline of forensic evidence can assist investigators to analysis specific evidence to identify its significance in the investigation.
When a crime occurs an investigator arrive at the scene of the crime there first set it collect and document all the evidence found at the scene of the crime that looks like it make be out of place or help draw connections to the culprits of the crime. If hair, fibers, fingerprints, tire tracks, bite marks, etc. are found at a crime scene those materials or makes are correct and examined through the use of forensic evidence. The goal of forensic evidence is to analysis the materials collected and draw connections through science to link specific individuals or objects to the crime scene by matching the scientific components.
This information is helpful to an investigator because it can provide time estimates of when the crime occurred, if the crime occurred at the location, who may be involved, what may have been used to commit the crime, etc. , but overall what caused the crime to occur. 5. Identify ten separate areas of forensic science that would commonly be utilized at a crime scene investigation and give a brief explanation of each. Hair analysis is the examination of human or animal hair. Forensic science is able to distinguish the difference between the two.
Depending on the sample and if the follicle is still attached, science can recover DNA from the hair. Difference can also be made between what area of the body hair originated from. Fiber analysis is the examination of man-made fibers. Forensic science is able to identify through different processes the origination object a fiber may have come from and also may be able to identify what action cause the final location of the fiber. Fiber location can be a good indicator of a struggle or specific actions during a crime.
Tread analysis is the examination of treads or tire marks. Upon discovery treads or tire marks are photographed and sometimes casted for examination. These photographs or casts are analyzed to determine the type of vehicle the treads could have come from. Ballistic analysis is the examination or firearms and ammunition. When cases involve firearms and ammunition, ballistic science is used to identify the characteristics of the ammunition discovered and link it to the type of firearm or exact firearm through the identification or rifling in the barrel or the firearm.
Glass analysis is the examination of glass. Forensic science can examine glass to identify its refractive characteristics or composition to connect it to other samples of glass collected. There are numerous types of glass and forensic science is able to assist in identifying and matching samples. Paint analysis is the examination of paint samples. Forensic science is used to link paint samples recovered and link those samples to a source of origin. Paint analysis is common to link vehicles and weapons to a crime. Soil analysis is the examination or soil particles.
Forensic science can identify even minute traces of soil particles and identify its characteristics, possibly origin. Footprint analysis examines the foot or shoe impressions. Forensic science can indicate through photographs or castings the size of foot, if it is human or animal in origin, if the speed of the individual, type of shoe the individual was wearing. Fingerprint analysis examines human fingerprints. Each individual person has different fingerprints and forensic science can examine one fingerprint and link it to a specific individual.
Blood spatter analysis is the examination of blood and how it arrived at its discovered location. Forensic science can analysis blood spatter to indicate the origin of the blood and what may have taken place in what direction and matter to cause the specific patterns of blood discovered. 6. What can a forensic scientist/expert ascertain from hair samples located at a crime scene or on a victim? What would the expert be able to testify to upon analysis of these samples? Hair evidence is commonly discovered at the crime scene because both humans and animal are always shedding hair.
The important job or hair forensic analysis is to discover the origins of the sample collected. If a hair sample still have a follicle attach it is possible for a forensic scientist is acquire a DNA pattern from the hair. The characteristics of a hair sample will also indicated the type of hair and location of the body where the hair would have originated from. Examination of the hair root can indicate whether the hair was removed through force or naturally shed by the body. At trial the expert may testify to the all the characteristics able that are possible to discover through a hair sample.
Also, an expert may testify to the location of hair and how the characteristics of the hair sample may indicate a certain type of behavior for that hair to be found in the location it was. For example, if a male pubic hair is found in the location or a female genital area then that may be an indication of sexually deviancy. All of this testimony would be circumstantial and only a presentation of possible reasoning for hair characteristics and location. 7. How was fiber evidence utilized to convict Wayne Williams in the Atlanta Child Killing murders?
Williams was convicted using seven different fiber and hair associations to the victim Jimmy Ray Payne. Payne was found in a river, but his cloths still retained fibers that were left on the body from his contact with Williams. The medical examiner was able to recover these fibers and sent them in for forensic testing. Through forensic testing it was found that two different fiber strands were consistent with the characteristics of Williams’ bed spread and bedroom carpet. Other fibers retrieved from Payne were consistent with William’s car.
Other fibers where connected to various fibers throughout Williams’ home. Once the fibers were from Payne were linked to Williams, the FBI examined the fiber evidence from eleven other victims and through consistencies between all the fibers that were collected where able to link Williams is some way to all twelve murders through the fibers evidence. 8. How can certain marks located on a bullet be analyzed and used to help determine the exact gun from which the bullet was fired? Each individual firearm is created baring its own rifling.
Rifling is the groves located within the barrel of a gun that assist the bullet to spin while exiting the gun and pierce through the air without wavering or tumbling. The rifling of the gun leaves distinct marks on the bullets that allow the bullet to be traces the specific rifling of the gun that shot the bullet. If there is no gun present to be directly compared to the bullet, rifling can also being used to identify the specific caliber or mark of the firearm used to fire the bullet. 9. How could glass or paint evidence be used to help solve a hit-and-run motor vehicle accident?
What would the forensic expert be able to testify to when comparing glass or paint located at the scene in order to trace paint or glass evidence located on a suspect’s vehicle? Paint and glass evidence can be crucial in linking suspects and vehicles used in hit-and-run crimes. In most hit and run cases, when a vehicle strikes an individual or object traces of paint and glass may be transferred from the vehicle to the individual or object that was struck. Paint evidence is limited to the size or the sample and amount of paint transferred during contact.
If the paint characteristics are identified, then those characteristics can be used to link the sample to the type or paint and color. If paint and color can be found and glass samples are left at the scene of a hit and run it is likely that the type of vehicle can be identified. Different types make, models, and types of vehicles utilize different types of glass in the construction of the vehicle. Glass forensic evidence can use glass sample taken from the scene to identify the type of glass and compare it to other samples to indicate possible origins of the sample.
An expert witness cannot directly implicate a suspect in a crime by the glass or paint evidence from the scene of the crime and sample taken from the suspect vehicle. However, the expert witness can testify that the samples from the suspect’s car and the evidence collected from the scene have the sample characteristics. Also, an expert may be able to show that the damage or striations found at the scene could indicate that the car’s damage could have been directly caused by striking the individual or object involved in the hit-and-run.