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DNA Profiling and how is used to Solve Crimes: Case Study 1

There exist different kinds of crime scenes. However, every one consists of different kinds of evidence that can be collected. These types of evidence can range from individuals’ fingerprints and DNA. Notably, DNA plays a significant role in forensic biology. It helps to prove beyond doubt that an individual has committed a particular crime because people do not share the same DNA unless they are identical twins. Further, DNA helps to prove than a person is innocent. After samples of evidence have been collected from the crime scenes, a DNA test is conducted to establish any relationship between the results and the forensic details of the suspect. This paper analyzes a case of where two suspected individuals robbed and shot dead a man and his wife on vacation in Paris. A physical interaction occurred between the individuals. Therefore, DNA profiling will help to relate the evidence at the crime scene and the individual profiles in the police custody in order to convict the criminals.

DNA profiling refers to a forensic method used to compare criminal or suspects profiles to the available DNA evidence, to establish the likelihood of involvement in crime. DNA profiling involves different procedures. Here, small portions of DNA variations are tested through forensic investigations to differentiate between individuals. DNA profiling was developed in 1985 by Alec Jeffreys from Leicester University. DNA profiling is a process where a particular DNA pattern is collected from an individual. Once the samples of evidence of the two suspected criminals are collected from the scene, a Short Tandem repeat sequences (STR) will be used to profile individuals’ DNA. STR analysis is a sensitive process whereby the traces of a person’s hair, skin cells, and tiny blood droplets are run through a test to confirm the results (Payne-James, & Byard, 2016). In this case, the evidence collected from the scene such as blood, hair remains, sweat and others will be taken through STR analysis. After, STR analysis, both profiles collected from the scenes will be compared and related to the profiles in police custody. This will help to find the likelihood of involvement of the two men in the robbery with murder case.

The importance of DNA profiling in criminal investigation cannot be overemphasized. First, it used to identify the potential suspects, linking them to the crime by proving that the criminals were at criminal scene. For example, when conducting a criminal investigation, the investigator will collect any essential evidence from the criminal scene. The samples of the collected blood, hair, sweat collected from the scene will contain adequate genetic details of the two suspects in the robbery with murder case. Upon collection of the samples, their DNA is extracted from the samples. This will be used by forensic investigators to construct a DNA profile from the materials collected from the crime scene. Forensic DNA profiling will help to compare the evidence collected from the crime scene and the profiles of the men that already exist in the police custody. When the profiles derived from the criminal scene corresponds to what the police have, it will be clear that the same suspected men must have been involved in the robbery with murder case.

Further, DNA profiling enhances accuracy in the criminal and justice system. To obtain accurate details about the suspects, their DNA must be amplified. DNA usually has coding consequences and non-coding consequences. The STR sequences are 4-10 nucleotide sequences that are often present in an individual’s DNA non-coding region. During investigations, forensic investigators analyze different types of STR sequences. These reveal genetic information about individuals. In this case, the DNA is collected from the samples of blood retrieved from the crime scenes. These samples must be taken through a forensic analysis process to establish their genetic profile before being compared to the previous DNA profile stored by the police. When the profiles match, then then the two men suspected become the offenders. This is more accurate way of knowing the perpetrators.

Evidence occurs in different forms. While some evidence can be removed or manipulated, others cannot be erased from the crime scene. Whether robbery, assault, or murder, like in the present scenario, there is a lot of physical evidence that can be collected from crime scenes. In this case, the physical evidence collected from the scene will include blood, hair, footprints, sweat, and other body tissues (Faleti, 2017). Since there was a physical interaction between the victims and the suspects, these evidence can be adequately obtained from the scene. Once the traces of evidence are collected, DNA analysis is conducted to confirm whether the profiles of the samples collected match the profiles of the suspected individuals. Hair remains can also be collected. During the struggles, the hair traces can remain at the scene. Therefore, this is one of the most reliable form of the physical evidence that can be obtained from the scene. Another physical evidence that can be collected from the scene is sweat. Averagely, a square inch of the skin contains 650 sweat glands (Ajanovoska et al., 2017). When bodies move and get involved in the struggle, small amounts of sweat are left. Sweat remains can be collected and presented to forensic chemists for further analysis. Blood stains or smears are essential form of physical evidence. The blood stains can be collected from the victims clothing, traces of weapons used or even the blood deposited at the scene itself. Dry and wet blood stains is a sufficient evidence that can be used to identify the suspects.  A complete blood analysis through typing in a number of systems can be carried out on a stain the size of one square inch and still leave a portion of the stain for courtroom presentation (Payne-James, & Byard, 2016).

There are different kinds of DNA tests. In this case, nuclear DNA test is the most suitable. The nuclear DNA is inherited from both parents. Of all the DNAs, nuclear DNA is the unique type of DNA; it can only be shared with identical twins (Butler, 2014). Unlike mitochondrial DNA testing, nuclear DNA testing is more effective in forensic investigations. In this case, the samples of evidence collected from the crime scenes are collected and compared to the available forensic details.  Here, a nuclear DNA test reveals the exact and unique information about an individual.

Each type of piece of evidence has a unique type of test. To examine blood, various tests can be conducted. However, the Luminal process is more effective in this case. Here, a chemical on the bloodstains. After the Luminal process is conducted, confirmatory test specifically. Takayama test. Here, the Takayama test is performed to confirm if the bloodstains exist state crime laboratory protocols. Shoe print evidence can be physically examined before being taken to the laboratory for further investigations. 

After conducting the relevant tests, the DNA profile of the samples collected from the scene is analyzed. Upon the examination, the profile is compared to the already available evidence with the police. When the samples match, the suspects are arrested and convicted for robbery and murder.

In conclusion, criminal investigation is not an easy process and there are cases where one gets wrongly convicted. However, DNA profiling has made the criminal investigation process easier. Through DNA profiling, samples collected from the scene will be analyzed and compared to the profiles in police custody.  Matching profiles means the same persons must have been involved in the criminal activities. Therefore, if the profiles from the scene match those with the police, then it is accurate that the suspects are real perpetrators. This will give the police a clear indication to convict them for involvement in robbery with murder.