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Introduction:A corpsewith serious injures  left  lonely  stretch  on rare area from thecity. A fire broke out at  a lawyeroffice just one day  before the court. Acar accident leads to claims the life of whole family . All previous cases are probable a crime scene.

Byestablishing methodical examination for the previous incidents  , investigators should be systematic at crimescene  while searching for physicalevidence which can arrest the penetrators. Also, this process must be bone withcare  in order to preserve the decisiveevidences from damages. At the scene the first officer arrived  is responsible for  defining the scene or evaluating the scene,establishing a systematic plan for   collecting evidence without  desiring them, secure  the scene that  is potential contain a critical evidence,recording the scene and determining the involved people in the case andpackaging and submissions of  evidence toforensic laboratories.  In thisreport we are going to  provide related  information to crime scene investigation ::-Crime scenework-Types ofphysical evidence.

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-Chain ofcustody.-Recordingcrime scene.-Crime scenesafety.        Crimescene workCrime sceneinvestigation is the meeting point of science , logic and law.

It is a processthat include purposeful documentation of the conditions of the crime scene. Also, it include the collection of any physical evidence that could  explain what happened and who did it. If we take a look at who ispresenting at crime scene?:1.Police officers: The first who arrive at a crime scene.

They arrest the perpetrator if  still around and call for an ambulance if necessary. They are responsible forsecuring the scene so no evidence is destroyed. 2.CSI unit:Who documents  in a detail everything in the crime scene andcollects any physical evidence. 3.

Medical examiner:They present in case of homicideto determine a cause of death and not always present.4.Detectives:They interview witnesses andconduct with the CSI unit.

They investigate the crime rely on  witnesses and physical evidence. 5.5.crimescene technician:A  highly trained professionals  who analyses the evidence  from a crime scene  and present findings basing on theresults  of their analyses. The commonworks of the technician are: -Collect, process, and analyzefingerprints-Collect physical evidence such as weapons.-draw crime scene sketches.-determine  which itemsshould be collected at the crime scene-List the evidence and prepare it for safely transpotation to thecrime lab-Takephotos of the whole crime scene.

 6.Specialists :Including entomologists, forensicscientists and forensic psychologists  toanalysis the evidences.Ifwe talked in detail about  the duties offorensic scientist :Carrying  out laboratory examination and analyses submitted  by law  enforcement.–Serving   as  expert witness  in  a court  of  law.-Carryingout tests  using scientifictechniques  such  as infrared spectroscopy spectroscopy  massspectrometry  and  scanning electron  microscopy.-Ensuring  all laboratory  protocol  and regulations  are  followed.-Inputting  data  into computer  programs  and data base  Information.

-Preparing  written reports  .- -Coordinating  activities  related  to crime scene  collectionpreservation  and  transportation.-Serving  as  lesson between  the forensic  laboratory  and crime scene  Investigators.-Developing  ,maintaining and updating  work  quality standards  and  operating procedures.-Coordinating  work with  other  members of  forensic   term and  without side.Forensic scientists usually performtheir work in forensic or crime laboratory .

They are responsible for comparingand interpreting the physical evidence that was brought  by crime scene investigators. In specificcircumstances, forensic scientists may present at the crime scene  when the techniques of  the collection or preservation of thephysical evidence are in question. Types of crime scene:crime scene is the surrounding areawhere a crime has been committed.

Such as forest, road, house or it could beany place.  Crime  provide clues that help  in solving the crime which was committed. crimescene  can either be primary orsecondary. Primary scene is a scene where the actual  crime took place. For example , in a murderInvestigation , the primary scene would be the place where the murder occurredand the reason’s life was taken.

In addition,there might be additional crime scenes involved as well and it would be thesecondary crime scene. For instance , the criminal may have changed the placeof the body after the murder. Let’s say the body was removed and placed in  a forest then it would be the secondary crimescene. Secondary crime scene can help in finding more evidence which help insolving the case.  Scientificmethod to a crime scene investigator:  The successful certainlyobservations that the investigators found can be determine by the obtainedresults of the crime scene. The CSI should be methodical, reasonable and shouldunderstand: What are the physical evidences at the crime scene? The procedure to protect and collect these evidences. The approach of how to obtain observations from these evidences.  linking all the obtained results.

       Typeof evidences: Class versus individual features : The investigator of the crime sceneshould have the ability to differentiate between the class features of physicalevidences and the individual.  It is notpossible to identify all the physical evidences by only linking them to arelated item or person. Therefore,  thecrime sense investigator (CSI) have the responsibility to discuss all theresults of his forensic analysis with the scientist of the crime laboratory(lead detective) to find a cohesive and objective presentation of the evidence.Furthermore, biological or physical evidences can be included in the class orindividual features and sometime exclude persons from the investigateprocedure. Class characteristics:It is not necessary  that the physical evidence is related to acommon origin with a high degree of certainty, hence, only a group of sourcescan only be located into a class and not a single. For the differentiationbetween the class evidences, it is not always possible for the investigator tofind the exact or estimated probability values.

A good example of classevidence is  the polyester fibers.Investigation will collect information concerning the makeup polyester  fiber, but it is not possible to stateaffirmatively that the fibers came from a specific rug.  In addition, significance can be included tothe place and amount of the fibers regarding the murdered, suspicious and/orcrime scene. However, the investigators cannot accurately suggest that a specificrug was the source of the fibers.  Individual characteristics: Individual characteristics aregenerally considered as measurable differences evidences( physical andbiological) which permits it to be related to a single source with a high levelof accurately. This allows the investigators to identify the uniqueness of anysingle item of evidence. The mathematical likelihood which there are 2 matchingsources of the distinct evidence of individual is beyond human understanding .The forensic examiner can illustrate in the court the scientific outcome whichexcludes the probability of two identical sources of evidences (biological orphysiological) .

    Direct evidences: Direct evidence means that no needof further investigation due to an established fact. A good example for thedirect evidence is a recorded video of theft shop where the victim’s face isclear and easy to be identified or the permit of the eyewitness who was in theshop at the time of the shop robbery. Therefore, direct evidence does notneed  inference or hypothesis. It dependsto the knowledge or perception of the investigator and then directly confirm ordisconfirm the disputed fact.   Circumstantial evidence:Circumstantial evidences are themost evidences that are examined in the forensic laboratory, and it is dependsto the forensic scientist to illustrate an inference of his analysis to providethe fact. Therefore, this type of evidence is relies on reasoning and notdirect inference of a fact. To conclude, Circumstantial evidence is when theknowledge can be inferred from witness at trail.    Chain of custody:At the crime place, all theinformation of the crime scene includes individuals, action, permit, and theinvestigation documents an important link in the chain of custody.

 Chain of custody is a formal paper in order topreserve the physical evidences. Starting with the arrival of the investigatorsand the emergency people at the location of the crime scene, differentactivities are scrutinized by hundreds of people with different roles in orderto ensure that the justice is achieved. The protective procedures must bedone immediately at the place of the crime scene in order to protect all theevidences. Then, the access to the crime scene should be controlled and theinvestigation procedure  begun.The chain of the custody illustratesthe transformation of the  physicalevidences from the place of the crime scene until the investigator releases thecrime scene ……..of the disposal of the evidence.

                                                                                           Evidence submitted: To lab for analysis. Evidence received: By property/evidence unit Evidence collected: At the scene by CSI; entered on log and secures.                                                                      Evidence returned: To properly/evidence unit for storage                                                                      Evidence released: To CSI for court presentation Evidence returned: To property/evidence unit to await disposal Evidence may: Be returned to owner or destroyed (court determination scheme 1: chain of custody flowchart.

            Figure 1: shows chain of custody.            Searchingfor evidences:Crime scene technicians  are in charge of  providing a systematic strategy for  Searching for physical evidences  in order to preserve them from contaminationand damages and to cover up all types of evidences. Therefore  for each type of area there is a uniquepattern should be followed   to achievethe target.

The patterns the used in crime sceneinvestigations are:-Spiral searchmethod: all most this method applies forlarge areas which contains  tinyindividuals  in search. -Grind search method: it is  also used   forlarge areas that contains a abundant number of searchers. Also,  it is often used in open and woodland areas.-Line search method: thispattern used in moderate area with a few number of searchers.   -Quadrantsearch method: this method used for small areas. Figure 5: shows search patterns Recordingcrime scene:Recording is  one of the critical and significant  procedures in crime scene investigations  formany reasons. It is important  since itcan help investigators to gain a comprehensive overview  and inclusive knowledge about crime scene.

For instance, it can provides  areliable  material evidence according totheir  position and inter-relation  to scene as well as, it can provideswitnesses with ability to indicate the position of people and things withinscene and time of crime .  finally, itcan support the court restricting the scene in details  with potential evidence as well as refreshingmemory of assessor  of any incident. Recording crime scene can be doneby  photographs, notes and plans.  Photography:Photography  is one of the most significant methods thatused for recording crime scene   due to its ability to provides a virtualreality   picture for an incident.Although,  it can be useless or excluded  by the court in case that  is taken after any changemade at the scene  therefore, the mostrequirement for photography is the crime scene should be in unalteredcondition. Photographs should include:-Primary crime scene  and the adjacent area of area that incidentoccurs.-All objects at the scene  which can be used in investigation.

-All walls within the  place that crimetaken place and walls of  adjacent place.-Weapons used , surface under corpsand blood stains.-The relative position of objects aswell as body with adjacent  items in thescene.          Figure2: recording crime scene by photography.

   Notes: the purpose of writing notes is to provide an inclusive and certain  records about observations ,  sequence of events and examination  of crime scene. Notes which written at thetime of incident may be it is not at logical sequence but that producible and can be fixed later on  be reorganizing sequences in report. Inaddition, notes of events and observations maybe become non-significant or meaningful if it is writtenwithout indicating to some important details which is in relation with incidentsuch as ( when, where, by whom , how…) therefore,  notes should include: Time and date that investigators arrived. First person arrived at crime scene. Officer who was in charge about this case. Conditions of weather. The is the  incident and what was happening .

People and activities taken place.Investigators are in charge ofPreserving evidence therefore, they shroud concern about their movement pathway  while writing notes atcrime scene in  order to  keep evidence without damages andcontaminations.Plans:Plans are complement  details of notes and photographs as wellas  it provides specific details aboutdimension  and an overview  for scene by showing scales and the exactposition of items that related  to thescene.  There are several methods used toplans crime scene, Floor –plan is one way of planning  both outdoor and indoorcrime scene which illustrate  thelocation looking down from above. For instance, cross-projection or explodedview  is very close to floor-plans but itvary  in walls that folded to uncoveritems that founded in the walls. Isometric projection sketches also used toindicate items of physical evidence like bloodstains.

3D or tree-dimensionalsketches are new methods used in crime scene investigations which gives avirtual  reality picture for thescene.      However the most common plans usedfor crime scene investigation: Sketch plan ( rough sketch) :Sketchplan that drown at crime scene by investigators in order to show the positionof items and their relations with another items. Sketchplan contains:-structureor appearance of items in sketches by indicating each item by a number or aletter and provides a ligand for items.-sketchshould include time, date, and description of the crime.

         Figures3; shows rough sketches.        Scale plan (fished sketch):Scale plans sketches with accurate dimensional  size, shape and position .it considers more accurate an sketch plan since it isconcern about artistically  view  or appearance, accuracy  and it is drown with scales.    Figure4: shows fished sketches.            Collection of evidenceCrime scene investigation depend on the collection and the analysisof different type of evidence. There are physical and biological evidences. Thephysical evidence is any nonliving items and the biological evidence refer toany living being. Also, there is another important type of evidence calledimpression.

Impression is a patterns of the items when it contact with softsurfaces like shoes patterns. The collection of impression which found in crimescene is very helpful and important to the investigation. According to Locard’sExchange principle  that perpetrator whenenter a room he must leave something during contact with object or victim, andat the same time he must take something with him.   There are many differenttypes of evidence that can be collected from the crime scene such as :biologicalevidence including blood, hair ,body fluids and many other tissues.

Blood should becollected in clean gauze pad or clean sterile cotton and allow to dry at roomtemperature. Also, it should be refrigerated and frozen  and sendto laboratory as soon as possible. If there is dried blood on clothing, firstwrap the item in clean paper then place it in brown paper bag, seal andlabel  the container and never try toremove the stains from the clothes. Hair canadhered to a piece of film and sealed with polythene bag. Figure  5:collect blood sample by clean sterilecotton. Latent print Including palm print, fingerprint and footprint.

The collection of impression evidence need forensic specialist andcan’t just packed directly because it can be easily destroyed.Fingerprint is the most important evidence which gives direct individualinformation because no one have the same fingerprint even the identical twins. Dusting fingerprints with special chemicals is a way to collect latent print. Figure 6:collection fingerprint byblack powder. Trace evidence Including fibers, glass fragments and soil.

Wrap the glass and fibers separately in clean paper( envelopes)with lapels and send it to the laboratory for test. Digital evidenceIncluding cell phone records , emails and internet logs. Electronic devises , charges , cables and manual should becollected. Also, cell phones, thumb drives and hard drives should be collectedand examined by different tools and techniques in specialized lab.Drug evidenceDrug collection is based on the type of the drug. For instance,plant should not be packed in plastic because of the moisture and mold growth.

And if the drug is in syringes or other sharp object it should be packed hardsided packaging like cardboard cartons or glass vials then labeled thebiohazards. Figure 7: use glass tubes tocollect drugs. Firearm evidence-Never send a loaded gun to the laboratory unless it’s taken inperson.

Also, firearm should never be shipped even if it is not cocked or onsafety.  -never shot from the gun before it is being examined  in the lab. What is more,  the firearm should not be cleaned the bore ,cylinder or chamber before submitting – do not placepencil or any object in the end of the barrel when pick up a firearm.- record the caliber ,model ,make and serial number of the firearm.- firearm should be packed and place in strong wooden box or cardboard to makesure that the weapons will not shift during the transition.

– gunshot and rifles should not be taken separately. Figure 8: gun collected in plasticbag.  crime scene safety:This may refer to the proceduresfollowed to control crimes there must be proper equipment to process the scenedepending on the situation to protect the body.

The scene has to be secured andprotected before you process it ,this is for the safety of the crime sceneofficers and everyone else. The first one is to put on latex gloves which areimportant for protecting evidence because they keep you from leaving fingerprints behind. They offer you protection from blood and other substances at thescene so remember to cover your shoes or boots with rubber boots when you areindoors. Photograph the shoes of everyone at the scene including the officersand the technicians, so that you can distinguish their imprints from those ofsuspects.

Pay attention to the types of shoes or boots you wear they must havea good attraction and ankle support and will offer you protection from hazardssuch as nails. A helmet is also important they light and easy to store and eyeprotection there might be chemicals processed depending on the situation. Figure 9: wear latex gloves toprotect you from dlood contaminations , diseases and protect you from biengsuspecious by lnot leaving your fingerprint.  Personalprotective equipment:Personal protective equipment (PPE)at the crime scene  is very important forthe crime scene investigator and they should take it into consideration inorder to protect themselves from any hazards that may occur at theinvestigation place. PPE may include wearing gloves, shoe covers, full bodysuits and safety glasses. The first responders at the crime scene shouldimmediately ensure that there is no threats to the investigators in the crimescene.

Therefore, preventive measure must be followed in order to reduce thethreat of any accidental contamination.   ConclusionThis report gives important information about crime sceneinvestigation. The persons who present in crime scene and their exact jobs.Moreover, the different types of crime scene (primary and secondary). Also, itshows information about the important procedures before starting theinvestigation such as approaching , medical assistant and crime scene securing.In addition, it gives all the important information about the  whole investigation procedures and the crimescene safety. References:Books:.The Practice of Crime Scene Investigation ,by John Horswell.

.Techniques of Crime scene Investigation,Eighth Edition , by Barry A.J Fifher,daived R. Flasher.  .Crime Scene Investigation, by JacquellineT. Fifh,Larry S.

Michael C. Braswell, Edward W Wallace.Websites: -Layton,Julia.

“How Crime Scene Investigation Works.” HowStuffWorks Science,HowStuffWorks, 2 Dec. 2005,“CSI Job Description.” How toBecome a Crime Scene Investigator,“Howto Become a Crime Scene Technician: Career and Salary Information.” CriminalJustice Degree Schools, 

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