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Laboratory report

Table of Contents



4Thought starters


6Procedure one – Inked Fingerprints:

7Procedure two- the Latent Fingerprints:

7Results and discussion

8Figure 1: the fingerprints used to identify the person who committed the crime

10Collecting of an Evidence

11Matching fingerprints

13Locating fingerprints




Fingerprints get defined as the impressions left as a result of the patterns of ridges found in fingerprints of an individual. Friction ridges are the portions of the epidermis that are usually found on a person`s fingertips. Fingerprints of human beings are said to be durable and unique among individuals; therefore, make it suitable for the long-term identity of people. However, there are some deliberate impressions of fingerprints which can be formed by the use of ink or another substance by transferring the friction ridges to particularly smooth surface such as the fingerprint card (Kasai, White & Nakamura, 2010).

Prints become employed by police in identifying the people who wish to conceal their real identities or identifying individuals who are incapacitated. Through the fingerprinting analysis, many crime offenses have been solved. The friction ridges are sometimes referred to as “epidermal ridges” since they are raised the portion of the epidermis layer of the fingers and toes. These epidermal ridges usually assist in gripping and also providing a sense of touch by amplifying the vibrations when fingers rub against a rough surface. However, the patterns of the ridges are not purely heritable character trait (Albert, Ricanek & Patterson, 2007).

This evidence gets proved by using identical twins in which their fingerprints usually appear to be different despite the fact that they resemble each other. Regarding phenotypes, the identical twins are quite similar, but on the other hand, their genotypes are different. The physical appearance of an individual becomes determined by three factors which are DNA, Random development Events and environmental factor. Some phenotypes such as blood group types are usually heritable and therefore are not influenced by any other factor.

Some of the phenotypes such as the height of an individual have got less heritability. Therefore, environmental control such as access to calcium and proteins also contribute towards the height of an individual. The friction ridges are also believed to have resulted from a combination of factors, but the random developmental events played a significant role in its formation. On the influence of phenotype, random developmental events are the primary challenge to explain (Saks & Koehler, 2005).

For instance, the cells of a multi-cellular organism divide mitotically to produce clones. As the cells migrate during their development, the cells are usually exposed to certain environmental influences, and this causes their phenotype to be different from those of their sister cells. One of the greatest systems of identifying any living organism is by using DNA fingerprinting. Every organism always differs genetically in its way but with the absence of triplets and identical twins. DNA sequence cannot be easily changed by any means, unlike the traditional fingerprints which can get altered through surgical operations (Casey, 2011). DNA fingerprinting systems are imperative for some application such as forensics and paternity testing. There are several applications of using DNA fingerprinting such as solving criminal offenses such as murder and rape. Also, it helps in conducting a paternity test and as well used in determining the authenticity of rare sports memorabilia. Therefore fingerprinting has aided in identifying the criminals accurately.


The laboratory test using fingerprints was trying to solve a problem that was associated with crime activities that took place in the neighborhood. The neighborhood arrived at a decision that laboratory test could assist in solving the problem. There were allegations that someone entered the room and stole gemstones that were in the room. The suspects were four men in the neighborhood where they were exposed to forensic science to establish among the four who was the real thief. The forensic science was expected to be the best was of identifying the man who was the thief. This was the considered to be a fair and sincere way of establishing the thief as the other methods tried failed as the accused men were not admitting. The forensic science used in the process carrying out the laboratory test was based on the fact that each man has a unique fingerprint. As a result, it was easy to establish the man who was responsible for the suspicious activity in the neighbor. The surface of the house was used in the process of carrying out the forensic science and the fingerprints of the men. The fingerprints as they appear on the surface of the house were then used to compare with the fingerprints taken from the men. Since the fingerprints of the men were unique and no one had similar figure prints hence identifying the fingerprints that were similar to that on the surface of the way was an easy task.

The aims of the fingerprinting laboratory can include the following.

1. The fingerprinting laboratory is aiming at identifying the characteristics of the fingerprints to identify the differences that do exist among them.

2. It aims at identifying the minutiae that exist within the fingerprints that are used in the laboratory test.

3. The fingerprint laboratory test is also aiming at undertaking the necessary comparison of the known and the unknown fingerprints.

4. Lastly, it is aimed at understanding the limitations that can be associated with fingerprint technology.


Thought starters

This helped in making the men know how their unknown fingerprints and the known fingerprint found on the surface of the house could be used in the process of establishing who the thief was. They were then in a position to understand how the forensic science was the most accurate ways of getting the thief hence making them trust that forensic science could play a crucial role in ensuring sincere results.

The men were trained first on how the laboratory would be conducted to establish the thief. This was important to ensure that the men could agree with the results of the laboratory test as they were made to understand how the process could be carried out. First, the men were made to understand the how unique fingerprints in human beings. This assisted in making them aware of the accuracy of the method of establishing the thief hence making the men believe in forensic science as the best solution to the problem. Second, the men were made to understand how the friction ridges do develop as human beings grow and how unique they are making it hard to find people who do share similar finger prints. Besides, the four men were informed about the number of fingerprints in human beings and the benefits of using fingerprints in the process of solving such problem. The men were convinced beyond reasonable doubts that use of forensic science could best solve the problem making them prefer the use of the technique to establish who was responsible for the crime.


The materials that are needed in the process of carrying out the fingerprint laboratory test can include the following:

1. Ink pads

2. White paper

3. Pictures referencing arches, whorls, and loops

4. Fingerprinting powder

5. Magnifying powders

6. Scotch tape, clear packing tape, and large one

Procedure one – Inked Fingerprints:

1. Divided the men into groups comprising two men in each group

2. Followed the steps in the list below to make fingerprints set. Each and every man made fingerprints from the five fingers of one hand and sometimes with both hands.

3. Made use of the ink pads, placed the fingerprints on a white piece of paper that was blank. This takes some practices before having good prints set.

4. Labeled each finger using the abbreviations below:

  • T to stand for thumb

  • I to stand for index finger

  • M to stands for middle finger

  • R to stands for ring finger

  • L to stands for little finger

5. Used hand lens, looked at fingerprints and tried to make an identification of the type of prints you have. Categorized the prints by using the following type of patterns: loops, arches, or whorls. Use the above images so as to identify these characters.

6. Identified variety minutiae, as many as possible can and listed them all.

Procedure two- the Latent Fingerprints:

1. Placed fingerprints using different objects in the room like, tables in the lab, mirror, or even beakers pieces of glass.

2. Used brush and fingerprint powder as demonstrated to cover the prints that were placed on different objects.

3. Placed a clear packing tape or a piece of scotch tape (large), peel off the fingerprint carefully and place it on a piece of an index card.

4. Made an identification of the loops, arches, and whorls that were there within latent fingerprints, which were lifted.

Results and discussion

The fingerprints of the four men were then compared with the fingerprint of the surface of the house. One of the obtained figure prints of the men was similar to the one in the wall surface making it clear that the man was the thief. The results obtained serviced as the evidence for the person who committed the crime. The four men were passed through the process of identifying the fingerprints that were similar to that of the surface wall fingerprint. As a result, the person whose fingerprint was similar to that of the surface wall was held liable for stealing the gemstones. He had no way to escape the blame of having committed the crime. The fingerprints were unique in their way making it clear that the similar finger right with the one that was on the wall surface was the person who was the thief. This played a crucial role in identifying the thief as the other possible methods of solving the problem had failed. The man who was found to be the thief according to the results of the fingerprints did not have any other grounds to escape from the crime case. The DNA fingerprint is a unique representation of the blueprint of the genetic makeup of the human beings. As a result, fingerprints played a crucial role in solving the crime problem. Having similar fingerprints with those of the persons who was the thief is evidence that the man was the thief. This is because the thief touched the door of the house where the fingerprints were taken to compare with the figure of the suspects. Therefore, the man who has similar fingerprints was responsible for paying the gemstones as having the similar fingerprints showed that he was the one whose fingers touched the walls surface.

Figure 1: the fingerprints used to identify the person who committed the crime


Id 1

Id 2

Id 3

Id 4DNA fingerprinting, also known as genetic fingerprinting is a scientific process application whereby DNA samples are collected and used in matching other DNA samples that may have been found at the crime scene. DNA fingerprinting process is used to identify the bodily fluid or blood that has been left by an attacker at the crime scene and when there is the impossibility for visual identification. In DNA or genetic fingerprinting, no individuals found sharing same genetic code not even those of the identical twins (Davies & Wilson, 2004).

DNA fingerprinting was in 1980’s for the first time. Premises of body fluid like blood, semen, saliva or other fluids left by attackers or killers at the scene of the crime are used for quick criminal investigations.

Collecting of an Evidence

DNA fingerprinting works in a way that the DNA or genetic structure of each does not resemble, and it is hard to fake, forge or alter in any way. It is very rare to find two unrelated individuals having comparable DNA in that there is some attribute similarity in their DNA fingerprinting, and they are not identical.

RFLP is the most common procedure in DNA fingerprinting, and it stands for Restriction Fragment Length Polymorphism. This is whereby sample segments from the DNA extraction are being cut by the special enzymes. The RFLP procedure is focusing on DNA’s repetitious sequences that greatly vary from one individual to another. Then there is a separation of these segments by the use of a technique known as Electrophoresis that is used to measure them by length. Representation is created using procedures that can be called Autoradiography (Cox & Mays, 2000). This procedure does produce x-rays that are comparable by overlapping x-rays. STR Test (Short Tandem Repeat Test) is the most recent form of test, which does consider the DNA segments counting the repeats number at different DNA sites that are normally thirteen. This can result in creation of multiple DNA copies by use of as little molecules where this procedure helps in producing DBA samples that are usable from single human hair (Saferstein, 2004).

Fingerprinting evidence has proved to be reliable in many cases, as it has been considered high tech way of solving crime cases. It has been reliable in many instances where at situations where there is no enough evidence fingerprinting has been reliable to prove the innocence of the suspects. The good thing with fingerprinting is that there are no identical fingerprints. The use of technology in crime investigations has played a crucial role in making the operations in the field effective and efficient. As a result, fingerprinting has been considered as among the best ways in criminal investigation process where the fingerprinting principle that two people cannot have same fingerprints makes the technique more reliable (Risinger, et al. 2002). In nay cases, fingerprint evidence has been considered reliable to many juries in the process of deciding cases that do not have sufficient prove of crime committed. The use of fingerprints has been based on the fact that fingers do contain ridges and whorls that are unique.

Matching fingerprints

The use of fingerprints evidence is based on two primary principles that include:

1. The friction ridge patterns of an individual that include the swirled skin present on fingerprints cannot change over their lifetimes.

2. No, any other person can be found to have same friction ridges pattern making fingerprints unique in each. Even identical twins are said to have different fingerprints hence making fingerprints a special and distinct way of showing identity (Garrett & Neufeld, 2009).

In the process of crime investigations, police officers are said to rely on the fingerprints in the process of identifying the defendants by ensuring that they compare prints that are found at the crime scene with the prints that are already contained in the police file. In most cases, police have files that do contain fingerprints of various individuals were the prints found at the crime scene are compared with already existing prints in the files. It is through comparing the fingerprints it the crime scene prints that the evidence is found showing the person who might be responsible for committing the crime (Schweitzer & Saks, 2007). For instance, FBI is said to have many prints of many people that it uses in the process of establishing the person responsible for a certain crime by comparing the prints found at the crime scene with the prints already in the file.

The fingerprints of an individual can be found in files for various reasons that can include assisting with crime investigations. The fingerprinting exercise can take place during the time when an individual is arrested or at the start of the certain occupation. Many fingerprint experts are said to disagree with the points that are needed in the process of declaring the necessary match between sets of fingerprints (Casey, 2011). For instance, some experts do declare that 12 points in common are crucial in the process of declaring the match while declaring that they need 20 common points in the process of establishing a match.

However, fingerprint image acquisition mainly considered to be an important step in the system of fingerprint authentication, since it is the one which usually determine the final print image quality. Also, the fingerprint image acquisition has an effect on the performance of the systems. There are various types of fingerprints readers, but the main concerning each is to consider physical differences that are witnessed between valleys and ridges. Fingerprinting is the most complicated way, in which living organism become identified. The fingerprint is part of a portion of the genetic material which contains characteristics which are one of a kind (Cox & Mays, 2000). However, fingerprints are not readily altered when it is deposited with a mummy since it makes it become a reliable forensic tool. Forensic science is the primary instrument of piecing together a crime scene. Over several years past, advances are getting made in the ways of collecting fingerprint samples and preserving them too. By keeping fingerprint samples well from contamination and properly storing them to prevent degradation, forensic science has made a step by allowing fingerprint samples as valid evidence.

Locating fingerprints

The friction ridges are said to contain sweat pores rows and sweat that is usually mixed with other oils of the body. Dirt is said then to produce fingerprints especially on a surface that is smooth. The experts of the fingerprint are said to use chemicals and powders in the process of making the prints visible to assists in making them identifiable. The visibility of the prints set can depend on the surfaces that they are being lifted (Albert, Ricanek & Patterson, 2007). With the assistance from computers based enhancement techniques that can ensure extrapolating of the complete pattern only from the fragments. The use of technology is considered important in the process of making the prints visible to the point of being compared with the known fingerprint. Laser technology has been employed in various situations to read marking that might be invisible making the fingerprint experts rely on the laser technology to retrieve identifiable fingerprints from surfaces. The age of the fingerprint sets is not possible to be determined to make it challenging in the process of using the fingerprints as the evidence in carrying out a case in the court of law. As a result, most defendants facing charges in the court try to defend themselves against the use of fingerprints based on the time they were found at the crime scene (Davies & Wilson, 2004). Considering that fact that the time the age of fingerprints cannot be established through the use of forensic science, the defendants can be in a position to defend themselves by claiming that they were at the crime scene a time before the crime took place. The fact that forensic science cannot establish the age fingerprints is the limitation associated with the use of technology in providing evidence of crime investigation using fingerprints.


People are usually born with ridges which have fixed patterns on each of their fingertips. These peaks form loops that are different in each including the identical twins too. Also, all other physical character traits can change, but the fingerprints do not change under any circumstance. Also, any injuries such as burns do not bring any change to the pattern of the fingerprint. The print designs get left on any surface we touch with pressure. According to Latent prints, the ridge imprints left on a surface are usually not visible to the naked eyes. Even though the word latent means invisible, according to the forensic science latent print is taken to mean any chance that is left by friction ridge without considering the visibility during the time it becomes deposited. The electronic chemical technique usually allows the visualization of invisible latent print regardless of whether they are from a contaminant or a natural sweat of the skin. Latent prints always contain less clarity and content since a small part of the surface of a finger may be overlapping with other fingerprints from different people. Because of the reasons above, the latent print usually contains sources of error in making its comparison. A print taken under controlled conditions, therefore, entails more details and clarity.

On the other hand, patent prints are caused by transferring foreign materials from a finger into an individual surface. A good example is the impressions made from wet clay and flour, whereby the two impressions are visible therefore they are photographed instead of being lifted the way latent prints are done. There are some materials in which patent prints can be left such as blood, dirt, or ink. Moreover, the patent print can be used to preserve actual print which can be presented later in case a need for it arises. Exemplar prints refer to the fingerprints collected from a subject deliberately, regardless whether for enrollment in a particular system or any other purpose. In a case of determining a criminal among many suspects, Exemplar prints are usually taken from each finger from one edge of the nail to the other. This includes the impressions of the four fingers and each thumb from both hands. The live scan can be used to collect Exemplar print and also by using ink on the paper card. A plastic print entails friction ridge impressions getting left on a surface that retains the exact shape of the rib detail. There are some examples plastic prints which include a melted candle wax and thick grease deposits on car parts, which are already visible prints, therefore, do not require any enhancement or clarity. Despite the fact that the plastic prints are usually visible, investigators should also make attempts at identifying other non-plastic impressions which might have been made from the same deposits.


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