Crime is as eternal as a society, meaning that crime will exist as long as there is a society. With advancements in science and technology, detecting and investigating crimes have also developed. The progress of forensic science has entirely transformed the methods of crime investigations. Forensic science is a crucial part of the justice system. Forensic science can allow societies to determine how and when a crime occurred and the key suspects in a crime. With forensic science, the authorities can examine physical evidence and feel confident in their decisions regarding a criminal case.
Understanding Forensic Science
The term forensic refers to an issue related to the court of law. Therefore, forensic science is the application of science to matters of the law. It involves associating people, issues, and places involved in criminal activities. It comes in handy in detecting crimes, solving them, and establishing guilt or innocence of an alleged crime. Forensic science enables experts to match DNA to an individual, learn the makeup of an unidentified drug, and understand blood spatter patterns, among other issues. The results of a forensic test usually serve as crucial evidence in courts of law.
Application Of Forensic Science In Solving Crimes
Both prosecutors and criminal defense lawyers rely on forensics to approve or disapprove the evidence they avail in court. For instance, if no witness exists, the prosecutor could use the evidence obtained from the crime scene to gather DNA evidence that helps link suspects to the scene. Forensics could even enable investigators to determine when a crime occurred, including the exact date and hour.
In a case of murder, forensic science comes in handy in identifying the victim and the possible murder suspects. For example, investigators can identify the body by analyzing the victim's dental works or skeletal structure. Forensics could also help narrow down or determine who the remains belong to, for example, a young man of 25 years of age, around five feet tall and weighing 130 pounds.
Forensics also help determine the cause of death, giving the authorities a clue on the murder weapon to search for, consequently forming a starting point for the search of the murder suspect. For instance, the police could establish that the victim was shot with a .45 caliber handgun. The police can then check the database for anyone who holds a registered .45 gun in the area.
Below are the typical applications of forensic science in investigating crimes:
Deoxyribonucleic Acid (DNA)
DNA plays a crucial role in forensic science, enabling authorities to convict the guilty and exonerate the innocent. The genetic material in DNA enables the law enforcers to identify the perpetrator of a crime by analyzing the biological evidence present at the crime scene. The biological materials could be anything from buccal swabs, semen, saliva, blood, and vaginal swabs. In most cases, these materials are deposited in small amounts on different surfaces at the crime scene without the perpetrator’s knowledge.
The investigators can identify the perpetrator by processing the DNA from biological materials and conducting a DNA statistical interpretation. Currently, hundreds of public and private laboratories perform thousands of DNA tests in California alone. In addition, they have extensive computer databases with DNA profiles from biological samples obtained from crime scenes, convicted persons, and people arrested for crimes. As a result, DNA analysis has helped law enforcement officers to solve crimes.
Forensic DNA testing does not just help hold the guilty accountable for their crimes. It also exonerates the innocent from criminal activities they did not commit. Before DNA analysis, many persons ended up in jail after wrongful convictions because of faulty evidence and witnesses.
Physical matching could range from simple tasks like matching the torn edges of a piece of wadding paper to the original paper from which the piece was torn. Investigators can also use sophisticated aspects of physical matching to gather the information that the court will accept as expert evidence. For example, the authorities could conduct physical matching on items like shoe prints, fingerprints, tool impressions, glove prints, tire prints, plastic fragments, and broken glass while investigating a crime. Investigators conduct two types of examinations: class characteristics and accidental characteristics.
Class characteristics revolve around items like tire prints, shoe prints, tool impressions, and glove prints. The authorities can classify and sort these items during an investigation based on their type, size, model, and pattern. For example, if the shoe prints belong to a particular class, investigators can narrow their focus to people with shoes within that class description.
Accidental characteristics are unique features and marks that develop on an item because of tear and wear. With items like plastic fragments and broken glass, the process of physical matching calls for higher levels of expertise. Some comparisons even call for photographic overlay comparison and microscopic examination.
Fingerprints are unique to a person, which explains why the forensic science of fingerprints has a long history in criminal investigations. Provided an expert conducts an investigation, courts usually accept positive fingerprint matches as proof of identity beyond a reasonable doubt. Before the modern advent of biometric scanning technologies and DNA analysis, fingerprints and dental x-rays were the only reliable means of making an objective identification.
Fingerprints are unique line patterns and ridges that appear on the plantar surfaces of our hands and fingertips. Since the 1800s, these unique patterns have been categorized into categories and features. These unique features allow a person’s fingerprints to be cataloged in a database or searchable system.
The impression of our fingerprints usually remains on the surfaces of items that we touch. Our bodies produce oil that acts like invisible ink, which adheres to the smooth surfaces that we touch. The invisible fingerprints are made visible by applying a colored fingerprint powder. This powder sticks to the oil, revealing images of lines and ridges that form a fingerprint.
Fingerprints can be exposed on surfaces like dry paper, plastics, paint, etc. Sometimes, fingerprints could be visible when a perpetrator touches a surface, and their finger has some foreign material like blood or ink on it. Investigators could also depend on molded impressions of the fingerprint when an individual places their hand on a malleable place like cheese or clay.
Most investigators understand ballistic analysis given the prevalence of gun-related crimes. Ballistics refers to the study of items launched into flight, how they are launched and how they fly. Investigators often study different forms of firearms, including handguns, shotguns, and long rifles. Authorities use various techniques in ballistic science to handle the unique aspects of guns and bullets. The role of ballistic comparisons is to determine if a particular gun was used to fire an unknown bullet or cartridge casing. This investigation is sometimes known as ballistic fingerprinting. The analogy behind ballistic comparisons is that if a particular gun touched a cartridge casing or a bullet, it would leave some identifiable marks known as ballistic fingerprints.
Guns are classified by their caliber, ejector mechanisms, chambering, and firing pin for ballistic purposes. At level one comparison, it is easy to make eliminations of suspect weapons. For example, if the police find a .38 caliber bullet at a crime scene, it is evident that the bullet could not have been fired from a .22 rifle. Investigators make more decisive comparisons at level two examination using chamber markings, striations matching firing-pin comparison, and ejector markings.
Another common form of ballistic science, in addition to a ballistic fingerprinting examination, is trajectory analysis. A trajectory is a path a bullet travels from when it leaves the barrel of a firearm to when it loses propulsion energy and comes to rest, usually after hitting the target. The flight of a bullet can be short, whereby the perpetrator shoots a victim at a close range. The flight could also be distant, whereby the target is one mile or more from the perpetrator.
A bullet travels in an arched trajectory or path when traveling a longer distance. The bullet will have a unique entry angle into the target upon reaching its destination. By considering the trajectory and the angle of entry, investigators can determine the geographic location where the bullet originated. A bullet's trajectory would also come in handy in determining where a shooter was located in cases where a bullet travels through various objects like the walls of a house before hitting the victim. Studying the bullet's trajectory will reveal whether the shooter was moving in a drive-by shooting case. If the shooter were moving, the trajectory would indicate the direction of travel.
Hair And Fiber Analysis
It is hard for a person to be at a crime scene without leaving something behind or taking something with them. This theory explains the exhibits of hairs and fiber perfectly. Humans are constantly shedding different materials from their bodies or clothing. Therefore, a perpetrator could leave hair strands from their head at a crime scene. They could also leave fingerprints on the items they touch and fiber of their clothing material.
A perpetrator could carry hair or fiber from the victim's clothing when leaving a crime scene. Analysis of hair and fiber provides corroborative evidence. Investigators can compare hair samples collected at a crime scene to a suspect's hair to establish similarity. If the hair sample has root tissue, investigators can conduct DNA analysis.
Blood Spatter Analysis
Also known as bloodstain pattern analysis, blood spatter analysis is a relatively novel forensic specialty. This forensic analysis comes in handy in a crime situation where blood marks are present. This analysis involves determining how blood is distributed at a crime scene. Specific distribution patterns are common whenever a victim sheds blood during an attack. Blood spatter analysis is helpful in crime reconstruction. It reveals how the perpetrator struck the victim and the direction of the attack. For example, if the perpetrator uses a bat to strike a victim, the victim’s blood will be distributed in a droplet spatter pattern behind the victim, in the direction of the strike.
This is the process of examining a dead body during an autopsy to determine the cause of death. Experts conduct an autopsy in a hospital in the pathology department. The police officers are often present during an autopsy, especially in the case of a confirmed homicide or a suspicious death, to gather evidence. While conducting an autopsy, a pathologist cuts open the body and carefully examines, documents, and analyzes the body parts to determine what caused the victim's death. The pathologist will also estimate the time of death by considering the common after-death (post-mortem) indicators. These indicators are the temperature, post-mortem lividity, the degree of rigor mortis, and the progress of decomposition.
Pathologists are also trained to determine the causes of death. The common causes of death are shooting, asphyxiation, electrocution, toxic substances, blunt force trauma, stabbing or laceration, depriving necessities of life.
Other Forensic Sciences
Other common forms of forensic sciences used in crime investigation include:
- Chemical analysis
- Forensic entomology
- Forensic Archeology
- Forensic Odontology
- Forensic engineering
- Criminal profiling
- Geographical profiling
- Forensic data analysis
- Forensic document analysis
- Crime detection laboratories
- Forensic identification sections
Crimes Commonly Solved By Forensic Science
In addition to murder, other crimes commonly solved with forensic science are sex crimes and drug-related crimes. Forensic science comes in handy in determining the chemical makeup of a drug in drug crimes to enable the police to determine if a person possessed illegal drugs. If the forensic examination results are positive, the prosecutor can use the result to accuse a suspect of possession of a controlled substance.
Forensic science is also effective in determining the drug that killed a person in the case of death by poisoning. It would also help to narrow down on the suspects who would have access to the substance used to kill the victim.
In a sex crime like rape, the DNA from the victim could be used to identify and convict the perpetrator.
Find a Criminal Defense Attorney Near Me
If you face charges for a crime in which investigators are bound to use forensics as evidence, it would be wise to hire an experienced attorney. Forensics are incredibly accurate, and if they reveal that you committed a crime, you could be behind bars for a long time.
The Law Office of Sara L. Caplan can investigate the evidence brought against you to help you create a viable defense in Los Angeles, CA. Contact us at 310-550-5877 and speak to one of our attorneys.