Forensic Swab: A Vital Tool in Collecting DNA Evidence
Forensic Swab |
What is a Forensic Swab?
A forensic swab is a simple cotton swab used by forensic scientists and
investigators to collect DNA evidence from crime scenes. Swabs are commonly
used to collect epithelial cells from areas like the mouth, cheeks, or under
fingernails which may contain DNA from a suspect.
Collecting DNA Evidence
It play an important role in collecting DNA evidence left behind at crime
scenes. When a person touches an object or surface, they leave behind
epithelial cells containing their DNA profile. Investigators use sterile cotton
swabs to carefully rub or swipe the targeted area to collect any deposited
cells. The swabs are then sealed and sent to a crime lab for analysis. At the
lab, technicians extract the DNA from any cells on the swab and analyze
specific locations on the DNA known as Short Tandem Repeats, or STRs, to
develop a DNA profile. This profile can then be checked against DNA databases
to potentially identify the source.
Types
There are a few different types of swabs commonly used for DNA collection:
- Buccal (cheek) swabs - Used to collect reference DNA samples directly from
the inner cheeks by gently rubbing the swab along the inner mouth area.
- Fingernail swabs - To collect any epithelial cells or foreign DNA that may be
trapped under a suspect's fingernails from scratching or grabbing a victim.
- Fabric swabs - For absorbing DNA evidence left on fabrics, clothes, or other
porous surfaces that may have come in contact with a person's external body
surfaces.
- Cutting swabs - When significant amounts of biological evidence like blood or
semen stains are present, cutting swabs are used which have a small plastic
guard or tube to protect the swab and collect a precise sample from the
cutting.
Proper Collection and Processing
Proper collection and processing of Forensic
Swab samples is crucial to obtaining high-quality DNA evidence. Swabs
should be air dried completely before sealing to prevent the growth of molds or
bacteria that could degrade DNA. Contamination is also a major concern, so
investigators wear protective gear and change gloves regularly. At labs,
stringent protocols are followed to analyze swabs separately and keep paper
trails to avoid any mix-ups. Even the smallest trace amounts of foreign DNA
left behind can provide important leads if collected and analyzed correctly
using forensic swabs.
Applications in Solving Crimes
Unsurprisingly, they have played a vital role in solving some high-profile
crimes over the years:
- In the Golden State Killer case, investigators were finally able to identify
the culprit Joseph DeAngelo after using DNA collected from decades-old crime
scenes left on fabric cuttings and comparing it to samples on a public
genealogy database.
- O.J. Simpson murder trial - Prosecutors relied heavily on DNA evidence
collected from blood drops at the crime scene, Nicole Brown Simpson's condo,
and a bloody glove and sock found outside O.J.'s house to argue his guilt had
he been convicted.
- 9/11 Terror Attacks - Swabs were taken from the World Trade Center debris and
used to identify over 1,000 victims and allowed closure for many grieving
families who could not visually identify remains.
- Hadden Clark Murder - Fabric swabs collected from the crime scene vehicle's
front passenger seat helped convict Benjamin Smoot for the strangulation and
murder of Clark despite Smoot's denial of ever being in the vehicle.
As DNA databases expand and new techniques emerge, forensic swabs will only
grow more valuable for solving unresolved crimes well after the fact by
generating new leads through familial searches or new DNA profiles being added.
Their usefulness at the front end of investigations should not be overlooked
either to develop targets or rule out suspects.
the low-tech cotton swab has become nothing short of indispensable in modern
criminal investigations. Through diligent collection and stringent processing,
trace DNA can be lifted from just about any surface touched by human hands and
shed epithelial cells. With new connections to genealogy websites, forensic
swabs provide a continuing avenue to solve decades-old cold cases. They exemplify
how forensic science has dramatically shifted criminal justice by augmenting
traditional evidence categories with compelling biological profiles
Get
more insights on Forensic
Swabs
About Author:
Ravina Pandya, Content Writer, has a strong foothold
in the market research industry. She specializes in writing well-researched
articles from different industries, including food and beverages, information
and technology, healthcare, chemical and materials, etc. (https://www.linkedin.com/in/ravina-pandya-1a3984191)
Comments
Post a Comment