Forensic science is defined as the application of various sciences to obtain answers to questions that the legal system is interested in. It is relied upon for criminal and civil cases. The earliest written record of using forensics for law enforcement purposes (solving crimes) goes all the way back to China’s Song Dynasty and a book entitled “Washing Away of Wrongs” from 1248. One record details how a death investigator discovered the identity of a sickle murderer. In 1909, the first forensic science school on Earth was opened in Lausanne, Switzerland. Since these dates, forensic science has become very important because it is used to definitively convict (as well as exonerate) people accused of crimes.
Fingerprints are mainly relied on for criminal identification, either after being taken by utilizing paper and ink or after relying on a computer database scan. Fingerprints can be used to prove a man or woman’s presence at a crime scene, but it can also be used for comparison with stored fingerprints of other offenders. Comparing fingerprints is based on comparing people’s friction ridges which is what makes up all fingerprints. In the past, analysts had to manually compared fingerprint ridges, but these days, computers are capable of recording and finding any comparable ridges.
- Intro to Fingerprints (PDF): This website provides a glimpse into how fingerprints are studied in forensic science.
- Forensics and Fingerprint Analysis: This website offers a brief look at the concept of fingerprint analysis.
Collecting forensic science evidence from fingernails is important to law enforcement. It is important because police can take scrapings from beneath the fingernails of victims at crime scenes. These scrapings will likely contain fine traces related to the crime itself, such as fibers, hair, skin or blood. Techniques of DNA typing are utilized to matter from under fingernails in helping solve crimes.
- Science of Fingernail Scrapings: A look at how fingernail scrapings are useful in criminal investigations.
Teeth are integral to forensic science because they can help in verifying somebody’s identity in the absence of DNA. Teeth are vital to law enforcement because they are able to survive attempts by criminals to hide evidence at crime scenes, such as by fires. Odontologists collect the victim’s teeth, take X-rays of them, and compare them to dental records for a possible match. Sometimes, simple bite marks on a victim can also be analyzed by odontologists to identify perpetrators.
- Forensics and Teeth Article: This website offers an article that details the work of forensic scientists looking at teeth.
Bones are important to law enforcement since they are relied on to determine a number of things about crime victims. These are the victim’s death manner, medical history, race, height, age and gender. Bones at a crime scene are brought to a forensic lab where anthropologists analyze them. There, anthropologists can reassemble bones as well as analyze different parts of the skeleton to determine the aforementioned information about a victim.
- Bones Video: This video presents a feature that shows how bones can be used in forensics to solve deaths going back to the 17th century.
- Forensic Anthropology Detailed: ThinkQuest looks at forensic anthropology, which is the use of bones to help solve crimes.
The skull is useful for law enforcement investigating crimes because it stays intact unlike other body parts. The skull is useful in determining information like the age and the gender of a victim. Anthropologists take the skull back to their forensic lab. There, they analyze the skull to look for the occiput, a bone near the back of the skull. If the skull belonged to a man, such a bone would be greater in prominence.
- What’s in a Skull?: This article focuses on advancements in forensic science, involving the use of skulls.
- Forensics and Skulls: This website explores how forensic science used 2D and 3D modeling to piece together mysteries.
Hair might be pulled out by the victim in a struggle for his or her life. Law enforcement finds hair important in an investigation because it can provide investigators with invaluable DNA details. Techniques like comparison microscopy can sort out all kinds of information on hair. This can be information like distinguishing hairs, whether the hair was shed on its own, or whether it was pulled out.
- Crime Scene Hair: This website details the usefulness of analyzing hair recovered at crime scenes.
- Hair Examination (PDF): This website features information on hair and its examination in crime scenes.
DNA provides law enforcement with a mighty tool for convicting felons and setting the wrongly convicted free. DNA typing works by scientists using DNA regions to create an individual’s DNA profile, which involves taking samples from hair, skin, blood, bone and tissues. In a criminal case, DNA samples of a crime scene and a suspect are extracted. These DNA samples are then analyzed and compared to see if there is a match.
- DNA in Forensics: This website provides information on how DNA is used in forensic identification.
- Criminal Investigations and Forensics: This website explains how criminal investigations rely on DNA to solve crimes.
Skin can be used to positively identify a dead body. Birthmarks and tattoos help in identifying a dead body because birthmarks and tattoos are almost like fingerprints in that they are unique. Forensic scientists will take photos of these skin markings and use them to positively identify the victim. This is the case if decay has disallowed facial identification.
- Skin in Identifications: This website looks at tattoos and birthmarks and their role in forensics.
- Crime Identifications: This website examines how tattoos are being used more and more to help solve crimes.
The study of feet in forensic science is called forensic podiatry. Forensic evidence connected to the feet can take on different forms, including pedal remains, foot impressions on different surfaces, and even footwear. Forensic scientists will look at the crime scene and deduce a person’s identify from this evidence. This involves unknown persons’ gaits.
- Forensic Podiatry Article: This article provides people with information on forensic podiatry.
- Crime-solving and Feet: This website reveals how feet can play a sizable role in helping to solve crimes.
Blood splatter at crime scenes
Law enforcement finds blood splatter analysis useful because it can inform them if a felony was perpetrated and if the blood was part of said crime. A forensic scientist usually has portable testing equipment with him or her at the crime scene, enabling him or her to test if the blood is human. A forensic scientist’s training will aid him or her in finding out the trajectory of the blood as well as the direction of movement of said blood splatter. Analytical computer programs may also be used to determine blood splatter information.
- Crime Scene Blood Splatter (PDF): This website explains how blood splatter is analyzed at crime scenes.
- Key Points on Blood Splatter: This website provides the points of key importance in blood splatter science.
Ballistics is important for law enforcement because it is used for the purpose of gunshot residue analysis. Sophisticated equipment such as a scanning electron microscope permits forensic scientists to analyze a bullet’s size and shape, while also finding out the exact composition in its particles. Forensic scientists analyze a host of factors in ballistics. They look at the gun’s particles, its bullets, the hand of the shooter, and elements that are close to a crime scene.
- All About Ballistics: This website provides a detailed look at the science of ballistics.
Rape kits are accumulations of biological evidence that are collected from sexual abuse or rape victims after an attack. A victim has to give his or her informed consent for the rape kit to be utilized. Collection involves going over the victim’s body—including the pubic hair region and the hymen—with swabs and other absorbing items to preserve DNA evidence. In some states, financial constraints make it impossible to actually process every rape kit submitted for evidence.
- Unused Rape Kits: This article examines why some rape kits are never tested.
- Rape Kit Information: This website reveals what a rape kit is and what it does.
The incorporation of footprints in forensic science is closely linked with forensic podiatry. In forensic podiatry, experts rely on a broad array of evidence connected to the feet, such as foot impressions and pedal remains, to come up with a suspect. In forensic science, footprints are analyzed by experts to determine facts like the gait of the individual to see if there is a connection to a crime scene. When analyzing footprints, experts might also look at footwear.
- Footprints and Height: This website features an exercise that shows how forensics can be used to tell a person’s height from his or her footprints.
- History of Footprints: This website looks at how footprints have been used in forensics.
When a vehicle drives over a surface, tire tracks are the impressions that said driving leaves on said surface. Tire tracks are very important to law enforcement because it enables it to determine what vehicle was being driven at the crime scene. The chemical analysis of rubber by forensic science allows investigators to now be able to characterize certain tire tracks. Investigators usually take photos of the tire tracks, measure them, and even make casts of them.
- All About Tire Tracks: This website explains the usefulness of tire tracks in an investigation.
- Tire Track Basics: This website looks at how tire tracks are important in forensics.
Serial numbers being tracked to perpetrators
Serial numbers can be used to track criminals through serial number restoration. If a serial number on an item like a gun has been filed, ground or taken off by other means, forensic scientists rely on chemical and physical ways to enhance faded numbers. Restoring a serial number helps law enforcement investigators find out information on a gun. This may lead to a suspect.