DFO Case Study Essay

When it comes to fingerprints, no two individuals are the same. This is just one of the many reasons to as why fingerprints are so important when it comes to evidence. In addition, fingerprints are used to assist in capturing the individual, who was at the crime scene when the crime was perpetrated. Fingerprints are found on surfaces due to the friction ridges that are on each one of our hands (Nolo, 2015). Sweat, body oils, and dirt are just a few of the things that

When it comes to identifying people that have committed a criminal act, the most positive means is through fingerprints. When we are born, our fingerprints stay with us until we die and our bodies start decomposing. To the human eye our fingerprints look the same, however, further investigation will show that each of us have a unique set of friction ridges that comprise our fingerprints and sets our identity apart from each other. At a crime scene, there are two different types of fingerprints that may be found. Patent prints are visible to the human eye. Latent prints are “unintentional prints found on items of

Latent fingerprints found at crime sights or else developed in the laboratory are categorized by examiners as patent, latent, or plastic impressions1. The word latent means hidden or unseen. Latent prints are undetectable until brought out with a physical, chemical and fuming process. The physical developer is a means to detect fingerprints on dry and wet, including paper articles, clay-based products and adhesive tapes. Ninhydrin is one of the most widely used chemical reagents for enhancement of latent finger print impressions on porous substrates. Nonporous surfaces do not absorb. These surfaces repel moisture and often appear polished. They include glass, metal, plastics, lacquered or painted wood, and rubber. Superglue (cyanoacrylate) fuming is the best example for such non-porous substrate analysis.

In quadrants 1 and 2 how the amount and constituents of the fingerprint residue on the substrate affects the fingerprint image, is determined. In quadrant 1, excess sebum and moisture is first removed from the finger tips with the help of a clean cloth. In quadrant 2, fingertip is first wiped around the nose or forehead to create excess sebum. Quadrant 3 and 4 were used to compare the details between untreated and dusted fingerprint residues.

Lee, H. (2001). Advances in Fingerprint Technology, Second Edition, 2nd Edition. Retrieved January 26, 2015, from Vital Source: http://online.vitalsource.com/books/9781420041347

Method used: I used my latent fingerprint dusting powder in order to bring the print to a visible state to the naked eye and then I used my tape I had to gain a copy of the print off the handle. I then took the evidence to my forensic vehicle in order to keep it secure for further examination.

Explain the principles and processes used in the analysis, comparison, evaluation, and verification of latent fingerprints. Latent prints are formed when the body’s natural oils and sweat on the skin are deposited onto another surface. Latent prints can be found on a variety of surface they are not readily visible and detection often requires the use of fingerprint powders, chemical reagents or alternate light sources. Generally speaking, the smoother and less porous a surface is, the greater the potential that any latent prints present can be found and developed. Investigators often perform cyanoacrylate processing, or fuming, of a surface before applying powders or dye stains. This process, typically performed on non-porous surfaces, involves exposing the object to cyanoacrylate vapors. The vapors will adhere to any prints present on the object allowing them to be viewed with oblique ambient light or a white light source. (Latent, n.d)

Fingerprints can be taken from a crime scene in various methods. Fingerprints are classified into three categories depending on the surface they are found. Fingerprints on soft surfaces are most likely to be three-dimensional plastic prints such as soap, wax, wet paint, fresh caulk, etc. (“A Simplified Guide To Fingerprint Analysis”, n.d). The fingerprints on hard surfaces are patent or latent prints including blood, dirt, ink, paint, etc. transferred from a finger or thumb to a surface (“A Simplified Guide To Fingerprint Analysis”, n.d). Patent prints can be collected using photography. The prints are photographed in high resolution with a forensic measurement scale for the image for reference. There are multiple methods for discovering and collecting latent prints. Alternate Light Source (ALS) use

Two of the most commonly used chemical enhancements for plain dry paper is Ninhydrin and 1,8-Diazafluoren-9-one (DFO) both of which can be used individually and together. When they are being used together, DFO has to be carried out first. Both chemicals react with the amino acids in the latent fingerprint.

The world of forensic science is full of ever developing technology. Analyzing forensic evidence involves using fingerprints, hair samples, blood, footprints, bite marks, and other sources of material to help identify someone. Each small piece of evidence found at a crime scene can be crucial — leaving the slightest trace of saliva or skin cells can be what convicts a person. Few people know the importance of forensic science more than Steven Avery.

FINGERPRINT EXPERIMENT2AbstractLatent print residue is a combination of many substances excreted from the body. Latent print residues may be left from natural sweat on the skin or from a contaminant such as motor oil, blood, ink, paint or some other form of dirt. They may exhibit only a small portion of the surface of a finger and may be smudged, distorted, overlapped by other prints from the same, or from different individuals, or all of these in combination. The factors that affect the quality or presenceof latent prints include the conditions involved between friction skin contact and the objects that are touched. Pre-transfer conditions describe the condition of the friction skin and the amount and type of residue on the skin; and are affected

In this phase a variable light source was used to excite the fingerprint residue. This was done to obtain fluorescence from the fingerprint residue. Various spectral filters and a range of camera settings accompanied with different light sources were tested to see if any fluorescence existed. The images were compared with each other to figure out if any sample shows florescence under any specific range of wavelengths. Since, we were unaware of the fact whether the fingerprints were contaminated during any experiment we used various wavelengths for the substances that might show fluorescence under different wavelengths. The level of detail in the images remained the same as the previous phase of research and

The amount of information that can be obtained through someone’s hands is astounding. One can determine the years of scarring from hard work, or the blisters from misuse. The most information can be obtained at the very tips of fingers, and what they leave behind. Fingerprints supply great evidence to help identify who was there, and possibly how many people were there. However, the problem becomes that there are too many prints found at one scene. It is difficult to try and determine when they were made based on physical appearance and common techniques. Nowadays, the age determination of latent prints can be achieved with a new approach using the sweaty residue of latent prints, and a small electrical charge.

Every time somebody touches something, they leave behind a unique signature that forever links them to that object. This link is their fingerprints, which are unique to every person, for no two people have the same set, not even family members or identical twins. Palms and toes also leave prints behind, but these are far less commonly found during crime scene investigations. Therefore, fingerprints provide an identification process that is applicable to background checks, biometric security, mass disaster identification, and most importantly, crime scene investigations. Fingerprints are so differentiated because they are made up of distinct patterns of ridges and furrows on the fingers. The ridges are the “raised” portions of the prints, and the furrows are the “recessed” portions. This perceived uniqueness has led some people to falsely accept fingerprint analysis as absolute scientific fact. Although overall fingerprints are reliable, there are definitely situations where their accuracy can come into question.

There are three types of fingerprints that could be left at a crime scene. The three types are latent, patent, and plastic. Latent fingerprints are made from the oil and sweat on the surface of a person’s skin. This type of print is invisible by the naked eye and requires processing for visibility purposes. The process can be done using chemicals or powder. Patent fingerprints are made from blood, ink, dirt, or grease and they are visible by the naked eye. Plastic fingerprints are made when a person presses on wax, paint, or soap and they are visible by the naked eye. The three types of fingerprints help investigators discover who was at the crime scene which can possibly lead to the arrest of suspects.