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Processes of an Crime Scene Investigator


The primary goal of my prolonged project is to learn what steps a Crime Picture Investigator undergoes from the crime scene to judge and how a forensic scientist analyses the evidence. The start of this essay answer this question, but then later on I'll describe how my job developed and changed into a new final result.

What processes will a CSI go through from a criminal offense scene to judge.

At the Crime Scene: Landscape Recognition

When a CSI first finds the scene of a crime it's important that they commence to develop a knowledge of what took place at the positioning, before they learn to retrieve the evidence. This is vital as though they jump directly into the collection they could easily damage some evidence. Other officials at the picture may also destroy or damage proof unintentionally, therefore the CSI's first main concern is to secure the region in which the crime occurred. This could range from just one room, to a whole neighborhood depending about how large a location the crime took place upon. For instance if the criminal offense was an automobile robbery, the crime scene that are inside the automobile and the encompassing area, however if someone was murdered there may be evidence scattered about the vicinity, such as a blood trail. The core crime scene will be obstructed off primarily by the first officers that arrive on the landscape; however it are a good idea to secure a location that is larger than the crime picture, so most CSI's will block off a straight larger area after they arrive. That is to ensure that all evidence from the investigation can be accumulated without it becoming tainted.

It is imperative a CSI follows accurate legal protocol throughout the study of the field, so once the field is secure they could need to contact the neighborhood magistrate. This is because if the evidence is found in a location that is classed as someone's personal property, such as on their body or in their car or house, they have the right to refuse a search. Using a warrant present the officer can search the region without permission; it does mean that its admissibility cannot be questioned as easily in court.

Once a search warrant has been obtained the CSI can begin their first walk through of the scene. That's where they follow a pre-decided journey either through or about the scene. The road is chosen predicated on where research is least apt to be, so that there is as little disruption of the world as possible. Through the walk through they take notes on details that will only be present for a restricted time, these can be things such as what can be smelt, what can be heard, what are the conditions, such as temp, weather and period, and any kind of potential hazards which have to be attended to immediately.

Once they have gaged the scene, they decide if they need to contact specialists or get any specific equipment, for example if there is bloodstream spatter on the roof it can be much easier to for an expert to analyses it at the field, rather than to deliver a large section of the roof to the laboratory. During this time period they may also take time to speak to the first responders, to find out if they touched anything at the picture and to gather anymore information that may be useful whilst inspecting the picture. Also if the detectives have begun interviewing witnesses, they may also offer some more advice as to where may be the best destination to look for research first. Most CSI's do not speak to witnesses as they deal with physical proof.

All the information that is gathered helps the CSI to build up a logical strategy and form a plan concerning how to gather the data and where order, but first they must document every part of the scene. That is called the picture documentation stage or the next walk-through.

At the Criminal offense Scene: Landscape Documentation

The main aim of scene records is to make a record of how they scene came out visually during arrival. That is so that the forensics lab and the prosecution team can understand what the scene looked like, even though they may have never been there. To get this done the CSI runs on the selection of equipment such as a sketchpad, graph paper, pens, pencils, measuring tape, rulers and an email pad in order to accurately pull a representation of the scene. The most detailed form of representation is by pulling a sketch of the field. This may include specific details that may be important to the truth, such as room sizes, locations of important research and pathways that might have been taken through the home. This is important so that we gain an overall view of what may have taken place at the scene and where order.

As well as drawing sketches, they must photograph the field utilizing a digital or film camera with a variety of different lens and filters. They must do this before they touch or move anything so that they have an accurate representation of how the scene was remaining after the event. These are less correct than sketches when representing the positioning of items as it can be hard to display numerical ranges in photos. The CSI must be sure that they have a range of images from up close photos, to long shots, so that they have a variety to use as data. Long photos show the surface of the criminal offense scene or the view of a person room in one corner, whereas close up shots show specific pieces of information. All photographs that are used must have several included in the picture, and then be registered in a log. The CSI must log each photography that they take and then include details including the photograph amount, the particular date and time, the location and a description of what is in the photo.

To accompany the photos, especially in an instance that takes place over a sizable surface, a video can also be saved that will involves full a walkthrough of the arena. This assists give a much better understanding of the design of the field, as it offers details such as time ranges between certain locations

Detailed notes must be written at the world, which include all information on the CSI's observations. It is paramount that they remain objective whilst writing notes and they stick to plainly stating the facts, rather than developing conclusions before methodical proof. For example if there is a pool of the reddish liquid adjoining a body, they need to state that it is a reddish-brownish liquid, rather than blood because it can be some other element that includes a similar appearance to blood. Once all the paperwork is complete the CSI can get started to determine how and where order they are going to process the data.

Examining the scene

Before ploughing direct in, the CSI must make a decision which pattern of research collection they go follow. By carrying out a strategic style, it ensures that all areas of the landscape are analyzed and that nowhere is missed out or forgotten about. This is important so that facts if accumulated effectively and no evidence gets broken during the process. There are many different methods that can used to search different kinds of scenes but there are 5 that are used on a primary day-to-day basis.

These are:

  • Parallel
  • Grid
  • Zone
  • Inward Spiral
  • Outward Spiral

The parallel search includes a team of CSI's building a brand against one side of the landscape and working their way over the scene whilst residing in their parallel lines. It may also be done by one person if they begin in one area and keep repeating the process just a little further along the boundary every time, till they reach the parallel place from where they started out.

A grid search consists of two parallel queries, one in the horizontal direction and one in the vertical path. This method is more exact than a parallel search as the picture is researched more thoroughly, and therefore chances are that more evidence may be found.

During a zone search the world is divided into different sections, which can be each numbered for a guide. Each zone can be searched by the different CSI, so the search is completed considerably faster, or an individual CSI can search each area individually. If multiple CSI's are looking different zones, after the first search they may swap round in order to ensure that the region has been search effectively, and this nothing at all has been missed.

The inward spiral and outward spiral both follow the same rules, just in different directions. During the inward spiral process the CSI starts off at the perimeter of the field and works their way inwards, towards the center of the field. However during an outward spiral, the CSI starts off at the guts of the landscape, and works their way out on the perimeter. Both of the spirals can be performed clockwise or anti-clockwise depending on the landscape and the CSI doing the search. When doing the search the CSI must be sure you go through the scene from all angles as different shadows may help to display more evidences which could have normally been missed. They need to also make sure they remember to research as the offense scene will be 3d.


At the Crime Scene: Finding the Evidence


When many of these operations have been completed the CSI can get started to collect the physical evidence. Throughout the process they need to find, acquire, and then properly package every one of the evidence so that it doesn't get broken during transportation back again to the lab. That is important as it may need to be examined in judge if it web links a think to the crime. A couple of five main types of facts, that are: trace data, impressions, body fluids, weapons/ firearms and documents. These can all play an important part when discovering what occurred at the picture and who was simply involved.


There are 5 main types of evidence a CSI will search for though-out the offense scene. They are:

  1. Trace Evidence
  2. Weapons
  3. Impressions
  4. Body Fluids
  5. Questionable Documents

For each of these different categories the CSI will apply a range of different techniques to recover the data.


Weapons will be the first item accumulated at the arena, in order that they do not cause harm to any of the officials on the scene. Weapons come in a range of


When weapons are being used it can leave behind the feeling. 'Impression facts includes any markings produced when one subject comes into contact with another, abandoning some type of indentation or print out. Common such information encountered includes shoes or boots impressions, tire markings, and markings created by tools and similar equipment. ' (http://forensicsciencecentral. co. uk/impressions. shtml)

When tools or weapons are used in a crime generally marks will be left behind. You can find two categories that frequently used tools belong to, cutting devices and levering devices. Cutting musical instruments are items like a knife, saws and cutters, whilst levering instruments are items such as screw individuals or crowbars. When these instruments are used it is often with force. This means that a distinctive routine or indentation can be left at the field. This pattern can be cast using a silicon silicone. The cast can then be analysed and associated back to the object that induced them, hence linking a suspect to a offense.

Footwear impressions can be 2 or 3 3 dimensional and hyperlink visitors to the scene of the crime, as each time someone takes a step they may have left an impression behind. 2D impressions can be raised in a similar way to fingerprints by using chemicals, dyes and fine powders. 3D images can be created when someone steps on a soft surface, such as ground. A commonly used approach to recovering 3D images is to create an impression by using a casting material such as plaster of paris. If the concoction is poured in to the impression it hardens so that it can be removed and then analysed.

Impressions can be quite delicate so have to be handled carefully, in particular when they are in dust. These kinds of impression can however be lifted using electrostatic treatment. This calls for placing a skinny covering of conductive film in the impression, then a voltage is passed through it, triggering the particles to bounce onto the film. This results within an image of the impression still left on the film, which may be used for assessment. Impressions in snow can also be very fragile, so in this case Snow Impression Polish is used. It truly is put on the impression multiple times every short while and then left to dry out. Once dry it can be cast like any other 3D impression.

Footwear impressions can carry a sizable amount of information with them as different under soles have different patterns. These habits can be associated with a specific brand of shoe, and a particular specific as different shoes have different levels of wear. It is because when someone wears the shoes, specific damage can be triggered depending on the way in which they walk. If there is a suspect, a sample of their boots can be obtained, and compared to the impression still left at the offense scene. Because of the specificity of different shoes, if the suspects sneaker impression suits the impression kept at the field, they need to have been there.

Tire impressions can also web page link a car to a arena, as being a footwear impression links a person to the arena. If a car has drove more than a delicate surface at the world then an impression can be left of the tyres. These can be lifted in the same way as footwear impressions and then set alongside the suspect's vehicle. If a car is linked to scene it can then be examined just as you would look at a location, to see if there is any research present.


As well as boots impressions, a think can be linked to a crime scene using their fingerprints. The real human skin is made up of 3 tiers which each come together to form a design of ridges and furrows, that happen to be your finger prints. They are completely formed by enough time you are 24 weeks old, as they develop whilst you are in the womb. The routine of ridges depends upon how much you migrated around when you were in the womb, and this points out why everyone's fingerprints are completely unique. Each ridge includes a row of pores, by which we sweat. That is why when we touch a surface the design of ridges is left behind.

Even though everyone has very different finger prints, they are categorised into seven different forms.

  1. Loop
  2. Central Pocket Loop
  3. Double Loop
  4. Plain Arch
  5. Tented Arch
  6. Plain Whorl
  7. Accidental

Loops are categorised by way of a ridge that crosses in one part of the style, loops around and exits on a single aspect. Whereas an arch is a ridge that enters on area of the routine and exits the other aspect.

Fingerprints that are kept at the picture of a offense can be found in three forms, obvious, plastic material or latent. Apparent prints are those that is seen because they have been still left in a dried chemical such as paint. Plastic prints can even be seen but are in a very soft surface, such as putty and latent images are remaining by sweating and other oils on the skin, and cannot be seen without treatment. To get a latent print to be recovered for contrast and analysis it requires to be cared for. The method where it is cared for depends on the surface that it has been remaining on and the surroundings. If the printing has been still left on the non-absorbent surface, the most frequent method of collection is using powders or fuming.

Once the CSI has determined they are going to powder a print, they need to next decide which method they are going to use, and which natural powder. There are many different forms of powder that are all used for different situations and then for against different shade backgrounds. For example the black powder enable you to develop a print out on the light surface, but you may have to use a fluorescent powder against a darker surface. Alternatively the CSI may choose to use a Magna brush with a magnetic powder. This is more accurate than by using a brush as there are no bristles so there is less chance of the print out being smudged or overdeveloped. If either of the happen the printing cannot be used as it is ruined. To build up a print a very small amount of powder is located on the brush, which is then smoothly swept across the print. The powder sticks to your body oils that are in the printing, making it noticeable.

Once the print has been powdered, it could be raised using clear tape. The tape is carefully put within the fingerprint; this leaves an imprint of the fingerprint on the tape. The tape is then put together with a plastic cover this preserves the print out so it can be carried back to the lab for analysis easily. Once back again at the laboratory the printing can be scanned and converted into a digital image which may be used for comparison.

Another method that is often used is the use of ninhydrin or triketohydrinene. These behave with the proteins that are in the print to produce a purple colour. Once the colour is rolling out, around two time after program, the image can be raised like a powdered print out.

A more technical method is the fuming method, that can be done using either superglue or iodine crystals. This needs to be completed again at the lab as it consists of heating the chemical so the vapours combine with the printing, making it visible. The print needs to be photographed immediately as the image only will last for a restricted timeframe.

For a printing to be linked to a think in court it needs to be analysed by two CSI's. If indeed they both match the collected printing to the suspects print out, then the think will need to have been at the world of the criminal offenses.

Why I thought we would research Forensic Science

Due to the soar of tv programs around the main topic of crime, the job of any CSI can frequently be confused between fact and what we watch on Television. The role of CSI's and a forensic scientist is very important as they perform many jobs that are important in today's population.

Recent types of CSI

Interesting to others too

Through-out my research I have continuously discovered a variety of fascinating facts i didn't know before I lay out on my job. This made me realize that credited to popular Tv set series such as CSI and silent witness, there a wide range of misconceptions around the way the process of Forensic Knowledge actually occurs. I feel that due to its importance in today's society, it would be a good idea for me to share some of my knowledge with others as I am certain that they would think it is as fascinating a topic as I am.

This prompted me to discover a way to teach others about Forensic Science so when the chance arose for me to perform a weekend cub scout camp, with a theme, I jumped at the chance. The very first thing I needed to do was come it with the right programme. This supposed that I had fashioned to choose carefully which out of all the topics I possibly could cover could be the most education and interesting to the cubs.

The first matter I decided to defiantly include was fingerprints. This is my first choice when i had already done some quite in depth research into the different types and styles of images but also because I realized I could incorporate some fun activities in to the session. I started out by instructing them how are fingerprints are developed

Planned a course for students to study from my research


Ideas for future

In the near future I hope to continue developing my understanding of Forensic Science and Crime scene analysis and I believe the degree that I am studying in September will quench my thirst because of this. Also I would like to continue educating others using the knowledge that I have already gained, as the weekend away turned out to me that many people out there don't possess a true understanding of what Forensic Research actually is, and that lots of people apart from myself see it for the interesting and intellectually fascinating subject that it is.

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