Forensic Science

Forensic Science

Forensic science is the use of scientific evidence to the proof crime. Forensic scientists gather, reserve, and do an analysis of scientific evidence collected during the period of inquiry. Forensic scientist must travel to the scene of the crime to collect evidence; others are in the laboratory to analyze the evidence on items brought to them. Forensic scientists can also be witnesses of criminal cases and civil cases in court and can be in prosecution side or defense side. Blood stain on various object collected in the scene of study can be used to determine the criminal. Hair collected at the scene of the crime, and the information gathered from the scene of the crime can also be used to determine who committed the crime (Fraser 9).  The case that will be used in this paper is a controversial murder of Jose, and Kitty was committed their sons by Lyle 21 years and Erik 18 years on August 20, 1989. The killing occurred that evening in the family’s home. They shot Both Jose and Kitty several times in the kneecap to make the murders look like organized crime. The brothers then moved away from the scene of the crime and dumped their shotguns. They returned at 11:47 p.m., Lyle called 911 and claimed somebody killed their parents. The police suspected the two brothers suspects but lack evidence to link those brothers with the crime (Heide 5).

Crime Scene Processing

Crime scene processing is very important for any forensic science investigation. The first officer to arrive on the scene of the crime is supposed to secure the area of crime for the purpose of preserving the evidence. He or she must restrict any unauthorized movement within the scene of the crime. If the scene of the crime is left unsecured transfer, contamination or loss of evidence may occur. The officer collects relevant information and request for further investigation if need be. Depending on the type of crime the first officer to arrive on the scene of the crime may ask for several teams of an expert to be sent to the scene of the crime. The second priority in the scene of study is to separate the witnesses. Witnesses may not have a chance to share information with each other concerning the crime. Isolating the witnesses avoid them to create a story (Hayden 10). Questions like when a crime occurs, the victim of crime, perpetrator identity, who called in are asked to the witness.

The forensic investigators need to examine the scene to decide where to take a photo. The examination may be done in primary crime scene first and then in the secondary crime scene. The forensic examiner needs to examine the scene clearly. Photos of that area should be taken especially close up photos. All stationary object need to be included in the photo because they are needed for reference. The scene of the crime should view, and photos were taken at several different angles and various distances. Close up photos should be taken several so as to give detailed evidence. A perfect rough sketch of the scene of the crime is drawn indicating the position of any object/body and any other type of evidence (Hayden 11).  On sketch distance should be provided, and North labeled. All object distances should be measured from two permanent landmarks and any object in the locality of the scene of crime included in the sketch including furniture, doors, and window. If the crime scene outside includes the position of vehicle, hedges, building, trees and other structures in the sketch. A final copy which is a more accurate sketch of the scene of the crime is made and can be presented in court if the need arises. This neater sketch can be generated by use of computer program available.

Searching the evidence at the scene of a crime can be done by a single investigator or group of investigators. Patterns such as spiral, grid, linear, or quadrant are walked and evidence location marked. The patterns are regular to ensure that all areas are searched. The light source is required to find small materials such as hair and fibers. Vacuum bags which are clean are used to collect evidence. The flashlight is used for examination and forceps is used in the collection of material to avoid picking up extraneous things. All the evidence collected from the scene of crime need to properly secured, sealed and labeled. The specific guidelines are followed in collection and storage of the evidence. For instance, the liquid evidence is collected and stored in air tight container. After investigation evidence is allowed to dry and packed in paper bindle to be used in court proceedings (LaForte 45). The size of bindle depends on the size of the evidence it can be small or large. The evidence gotten from the crime scene may sometimes not match with the witness provided (47).The evidence log should have import information such as case number, inventory number, evidence description, suspects name, victim name, recovery date and signature of witness and who recovered evidence.

When the police came to the scene of crime although they suspected the two brothers, they did not order them to undergo gunshot residue test. Erik interfered with the source of evidence when he removed the shotgun shell from the flour. The security at home was tight although there was a vehicle that was stolen from the compound one week before the murder. This put the police at the dilemma of determining who the murderer was. Few months after the murder the two brothers led a luxurious life, so investigator suspected they killed their parents for an early inheritance.


Blood evidence has been used to provide information necessary to solve the cases in court. It is very important to document correctly, collect and preserve blood evidence. The absence of blood evidence may support or challenge the witness statement. Blood evidence if collected and stored properly can be used for many years from when criminal act happen. Blood evidence application can link or eliminate one as a potential crime suspect. In the last two decades, the technological analysis of blood evidence has greatly advanced. In the 1970s most laboratories used ABO blood grouping to characterized blood stains of most crimes. The DNA analysis was used in 1990’s to characterize blood stains which are an efficient method of determining key suspect of a crime. Nowadays there are three major categories of analyzing blood stains. They include analysis of antibody-enzyme and proteins available in the blood, analysis of specific DNA molecule in white blood cells, and Analysis of a given DNA arrangements that have been repeated several times to be detected (Lee 23). . Blood analysis can separate identical twins which may have the similar DNA profile but totally different antibody profiles.

Blood evidence can be applicable in cases where the attacker and the victim are near or in contact. For example, if the attacker stabs or hits the victims, blood could be exchanged during the struggle. If a suspect shoot victim some meters away. There are very few chances for blood exchange to occur. Bloodstain patterns give details about the position and all movements at the time of the crime, who struck who, and the manner of stuck. The investigator should collect representative blood samples of the marginal bloodstains, like the bloodstains that are far from the corpse and the main section of action. Blood spatter patterns that vary from the common patterns of the blood-spattered. These bloodstains provide valuable investigative information.  It is necessary the investigator look for blood traces leading out the scene of the crime. These trails could come from an injured suspect. If a suspect is recognized in a case, then they should be examined for injuries. The suspect’s injuries should be photographed and documented.

The blood evidence to be effective comparison analysis should be carried. The blood detected at the scene of the crime should be compared with the sample of blood taken from the victim and probable suspects. The comparison should be made between the genetic markers of the suspect’s blood and victim’s blood with the blood collected at the scene of the crime. The ABO blood test is done to the blood stain discovered on clothes of the suspect.  The first thing to determine in a sample of blood provided is ABO blood type. If they march further analysis is to the blood samples. This further analysis shows the likely origin of the blood. Documentation of location and any evidence noted at the scene of the crime should be done carefully. The collection should start with the most fragile or evidence that is easily lost. Blood evidence should not be exposed to extreme heat or humidity. It is necessary the bloodstained evidence be refrigerated while waiting for it can be taken to the crime laboratory (Martin and Cahill 16). The blood evidence should be taken to the laboratories as soon as possible to avoid spoilage.

In the case, the Menendez murder blood sample evidence could not show who committed the crime. When the two brothers entered into the scene of the crime before the investigator was interfered. The other reason is that there was no close contact between the victim and the suspects because the murder was through the gun shot. That is why this case took a long time for the evidence to be established.


FBI deduce that hair is the most important material in Forensic Science and are often used for providing hints as to the identity of a criminal or attacker. The hair discovered on victim’s body, or the clothes can be used to determine race and sex of the person who did the crime. The hair discovered on the clothes of a victim or on the body of someone who has been the victim of an assault can often be used to determine race and sex. It can also deduce DNA for assessment. Hair is a dead matter, but it contains DNA which is a very important in the forensic investigation.

Collecting Evidence

Hair is collected throughout the process of forensic science mostly at the crime scene. Hair is collected at varying points throughout the forensic science process but most notably at the scene of the crime and the autopsy stage. At the scene hair samples are gathered from the area surrounding and this can help separating individuals from police and narrow down the list of suspects. Painstaking and meticulous processes are used to collect these samples. They are carried by Scenes of Crime Officers (SOCO) who wears protective clothing in order their hair and clothing do not interfere with any pre-existing evidence. Hair samples are collected in tubes, varying vials and grip seal bags to eliminate cross contamination that may occur between collection time and proper analysis time. The second way of hair collection is an autopsy. The pathologist scrapes the skin and victim’s fingernail for hair stacked there. It is useful methods because when struggling the victims try to defend themselves by possibly biting or scratching their attackers. It is possible to collect animal hair at the scene of the crime. The hair collected is stored in the same manner so that further investigation and comparison may take place at other stages (Kobilinsky 3).

Hair sample, scene of the crime, blood evidence as well as DNA profiling did not provide enough evidence in accusation of the two brothers as the murderer. These are because the entered the scene of crime interfering with the evidence available. However, the enough evidence was found from the Dr. Oziel tape. The tape contained the conversation between Eric and Dr. Oziel his psychiatrist claiming that they killed their parents. This was the one that was used as prosecution them to the life imprisonment on 20th March 1996 (Heide 15).







Works Cited

Fraser, James Curtis. Forensic Science: A Very Short Introduction. Oxford: Oxford UP, 2010. Print.

Hayden, Donald A. Crime Scene Processing: Laboratory Manual and Workbook. Boca Raton: CRC, 2005. Print.

Heide, K. M. “Parents Who Get Killed and the Children Who Kill Them.” Journal of                      Interpersonal Violence 8.4 (1993): 531-44. Web.

Kobilinsky, Lawrence. Forensic Chemistry Handbook. Hoboken, NJ: John Wiley & Sons, 2012. Print.

LaForte, Michael F. Crime Scene Processing: Basic Principles and Practices for the Successful Identification, Documentation, Processing, and Collection of Evidence at Crime Scenes. Jacksonville, FL: Drummond, 2004. Print.

Lee, Gregory D. Practical Criminal Evidence. Upper Saddle River, NJ: Pearson Prentice Hall, 2007.

Martin, Laurie, Catherine Cahill. DNA Recovery from Latent Blood after Identification by Fluorescein. Journal of Forensic Identification 54.6, 660-667. Print

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