CJ 370 Unit 7 Assignment 2

CJ 370-01: Crime Scene Investigation II

Unit 7 Assignment 1

Purdue University Global

Unit 7 Assignment 1

The scientific method deals with the use of precision, objectivity, critical thinking, repeatability, all of which are needed for the proper collection and understanding of the clues that are present at a crime scene. The investigator has to have the critical thinking skills as to determine what took place at the crime scene. This paper will detail the scientific approach that is utilized to identify and collect different types of evidence such as trace evidence, blood evidence, and other biological evidence. All of these types of evidence is important to solving a crime.

The scientific method is used when processing a crime scene and it is a huge part of the reconstruction of a crime scene. Both legal and scientific methods are used when searching any crime scene. The investigator has to be able to think outside the box, have great writing skills, and apply the scientific method to identify and collect the different types of evidence (Foster, 2013).

There are two important parts of a crime scene and they are processing it and analyzing it. When the investigator is processing a crime scene, he or she has to take plenty of notes, photographs, they have to sketch the crime scene, and collect the physical evidence. All evidence has to be collected and packaged the proper way so that no contamination can happen. If contamination does happen to the evidence, it could very well destroy the entire case and if this were to happen a guilty person may walk free or an innocent person may end up going to prison. It is important that all of the steps are followed in the correct order and there is no room at all for any mistakes to be made. The scene has to be protected and only the necessary personnel should be allowed to enter the crime scene. Gloves, and other proper clothing should be worn as to not contaminate any of the evidence (Fisher, & Fisher, 2012).

The crime scene analysist is there to aide the investigators with the understanding of the events that happened at the crime scene and to learn the importance of the evidence and to help them to reconstruct the crime. This will involve the information and evidence that is recovered from the crime scene. Biological evidence that may be collected at the crime scene can be blood, this would more than likely be processed in a forensic laboratory by scientists that specialize in this area. Dried blood would be collected and packaged in a paper bag or envelope and labeled with the date and time, case number and the initials of the investigator, and then transported to the laboratory (Holtkotter, Schwender, Wiegand, Peiffer, & Vennemann, 2018).

Investigators may use luminol as the first source of locating blood evidence if it is not visible to the naked eye. If to much luminol is used, then it can affect the information from the bloodstains. This would mean that it cannot be packaged, and this is a reconstruction pattern. If there is hair or fibers at the crime scene, they are normally collected using a pair of tweezers, the hair or fibers would be placed onto a clean piece of paper that can be folded and packaged in a paper envelope and sent to the lab to be processed (Fisher, & Fisher, 2012).

The analysis of the crime scene involves making a permanent record of the scene by taking plenty of photographs, and the collection of the evidence for further examination. The blood is an example of biological evidence and also semen is an example as well. Both of these types of evidence would be analyzed by a person trained in this area. Two types of physical evidence that may be collected is the hair and fibers and all of this evidence has to be collected and packaged the proper way so that no contamination happens. Biological evidence may not only be collected at the scene or from the victim, but from surviving victims and suspects (Holtkotter, et al., 2018). It is important that the investigators and the people who are analyzing the evidence follow all the correct steps.

Crime scene reconstruction is used by nearly all analysts, and the scientific method is proven and accepted. There are at least six steps that are involved in the scientific method one is state the problem, two is develop a hypothesis, three is to test the hypothesis by experimentation this is done to see if the hypothesis can be proven, four is to form a theory, five is to use the theory in order to predict the events or results of what happened, and last is the theory becomes law and that it holds up under testing and it is accurate therefore making the theory a scientific law (Bevel, 2001).

A good investigator when arriving on a crime scene where there is a deceased body, would ask questions like is this a murder or suicide. He or she would determine if there was a firearm at the scene, they would check to see for forced entry, they would try to determine if the victim knew their attacker. If it is a female they would learn if she had been sexual assaulted, two types of biological evidence that may be present would be blood and semen (Osterburg, & Ward, 2014). These two types of evidence would need to be collected and packaged the proper way and sent to the lab.

The investigator has to follow all of the correct procedures during the collection of the evidence to make sure that both accurate and reliable scientific results can be obtained from the forensic analysist. If there is any evidence to be taken from the crime scene such as computers, or other physical evidence the investigator may have to get a search warrant. If one is not gotten and physical evidence is taken then it may destroy the case, so it is important that the rules be followed. All of the necessary personnel at the crime scene has to wear things like gloves, possible booties to cover their shoes, and this is done so that the evidence that is collected does not become contaminated (Fisher, & Fisher, 2012).

As long at the evidence was collected and packaged the proper way and there was no chance of it becoming contaminated then the evidence will be admissible in court. The investigator will be armed with the photographs, sketches, notes, and possibly video recordings from the crime scene. The chain of custody has to be followed. This will prove that the integrity of the evidence has been maintained. The investigator will be able to show the jurors that everything was done the proper way and that all of the rules were followed. This paper has shown the importance to collect both biological and trace evidence and the steps that are needed to package it the proper way. The investigator will do his or her best when it comes to the case going to trial and prove that everything was done the proper way (Delattre, 2011).


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