Nothing is more crucial to any investigation than the actions of the first officers on the scene and the actions they take regarding the preservation of the crime scene, detention of witnesses and an arrest if possible. The immediate objective of the first officers on the scene must be the safety of all parties involved and all else follows Crime scene preservation should be the most important step to any first responder.
This protocol should continue to be followed by anyone who processes the scene. From the moment the first responder arrives at the scene, he/she should exercise a pertinacious attitude to insure that curious onlookers and personnel who are not involved in a task related to the scene, remain outside the cordoned perimeter. Without this first step, evidence found at the scene can be compromised or worse destroyed which could result in possibly ruining any opportunity to create a strong case to arrest and convict a suspect. Once secured, the crime scene can be processed.
There is a basic protocol that all investigators follow and even though each crime scene is different with a vast array of circumstances the basic procedures remain the same. “Evidence used to resolve an issue can be split into two areas. Testimonial evidence and physical evidence. The testimonial evidence would be any witnessed accounts of an incident. The physical evidence would refer to any material items that would be present on the crime scene.” (Amos, 2011)
These items would be presented in an issue or incident to prove or disprove the facts of the issue. What will evidence collected at a scene do for the investigation? It proves that a crime has been committed, establish any key elements of a crime, link a suspect with a scene, establish the identity of a victim or suspect, corroborate verbal witness testimony, and exonerate the innocent. This would be the first task to perform. The investigator would interview the first responder and gather as much information from him/her as possible.
Some important points would be the type of crime that was committed, in what area it was committed, and how it might have been carried out. Other people who would be interviewed would be the neighbors, passersby, anyone who may have seen and/or heard anything that would assist the police in apprehending the perpetrator. Also, sometime during the investigation interview all associates and family members of the victim in an attempt to establish possible motives for homicide and identification of perpetrator. They will be more than happy to provide information.
Visit victim's place of employment or location of recreational activities such as a street corner. Some of the challenges confronting an investigator during this phase could be neighbors giving conflicting information regarding what was seen or heard, finding those individuals who were in direct proximity of the crime scene prior to and immediately after the crime was committed, or not having any witnesses at all.
The evidence that is located and recovered at a scene will give the detectives responsible for the investigation leads to work with in the case. The types of evidence that can be collected are, impressions include fingerprints, tool marks, footwear, fabric impressions, tire marks and bite marks. Forensic Biology includes blood, semen, body fluids, hair, nail scrapings, blood stain patterns.
Trace Evidence includes gunshot residues, arson accelerant, paint, glass and fibers. Firearms include weapons, gun powder patterns, casings, projectiles, fragments, pellets, wadding and cartridges. “Run a gun check if a firearm has been recovered and have the firearm traced...after it has processed by Crime Scene Unit. Confer with ballistics and make frequent follow up inquiries since a gun not recovered may be used in another crime at a later date.” (Fielder, 2011) The recognition or discovery of evidence begins with the initial search of the scene.
“The search can be defined as the organized and legal examination of the crime scene to locate items of evidence to the crime under investigation. There are several search methods or patterns applied in an organized search. Factors such as the number of searchers, the size of the area to be searched, the terrain, etc. are used to determine the method or pattern to be employed in the crime scene search.” (Amos, 2011) Since most investigations start with very limited information, care and common sense are necessary to minimize the chances of destroying evidence. A plan of operation is developed and initiated from an initial walk through of the scene.
The plan is to decide what evidence may be present, what evidence may be fragile and need to be collected as soon as possible. What resources, equipment, and assistance are necessary for the processing? Consideration of hazards or safety conditions may need to be addressed. In the documentation stage of an organized approach for processing the crime scene all functions have to correspond and be consistent in depicting the crime scene.
The final results of a properly documented crime scene are the ability of others to take the finished work and reconstruction the events that occurred at the scene and make a court room presentation. In the Scene Documentation stage there are three simple steps to properly document the crime scene written notes and reports, photographs, sketching. Each method is important in the proper documenting of a crime scene. “The notes and reports should be done in a chronological order and should include no opinions, no analysis, or no conclusion.” (Brown, 2011) Just the facts!!!
The scene should be documented just as the investigator sees it. The photographs should be taken as soon as possible, to depict the scene as it is observed before anything is handled, moved, or initiated into the scene. The photographs allow a visual permanent record of the crime scene and items of evidence collected from the crime scene. There are three positions or views that the crime scene investigator needs to achieve with the photographs. Those views consist of overall scene photographs showing the most view possible of the scene, mid-range photographs showing the relationships of items and a close up of the item of evidence.
A close up should be taken of items that have serial numbers, tags and VIN’s. All stationary evidence where the photograph will be used to assist in the analytical process should be taken using a tripod with the proper lighting techniques for creating any needed shadows. A second photograph adding a measuring devise should be taken of items where the photo will assist in the analytical process. Sketches are used along with the reports and photographs to document the scene. A crime scene sketch is simply a drawing that accurately shows the appearance of a crime scene.
The sketch is simply drawn to show items, the position and relationship of items. It does not have to be an architectural drawing made to a scale, however it must include exact measurements where needed. The advantage of a sketch is that it can cover a large area and be drawn to leave out clutter that would appear in photographs. Examination of the crime scene will usually begin with a walk through of the area along the "trail" of the crime. The trail is that area where all apparent actions associated with the crime took place.
This trail is usually marked by the presence of evidence. Point of entry, location of a body, areas where the suspect may have cleaned up, and the point of exit are all included in the trail. The purpose of the walk through is to note the location of potential evidence and to mentally outline how the scene will be processed. The walk through begins as close to the point of entry as possible. The first place the investigators should examine is the ground on which they are about to tread. If any evidence is found, then a marker should be placed at the location as a warning not to step on the item of interest.
When searching for blood evidence, it is important to use a high intensity light. A high intensity light source will aid in the visualization of bloodstains, even stains that have been diluted. The light source can also be used to provide oblique (side) lighting. Oblique lighting is an excellent tool for finding trace evidence and other small items of interest. “Since blood evidence associated with a crime can provide information that may solve the case, it is essential to correctly document, collect, and preserve this type of evidence. Improperly handled blood evidence can weaken or destroy a potential source of facts in a case. Properly collected and preserved blood evidence can establish a strong link between an individual and a criminal act.
Blood evidence or the lack of blood evidence can also be used to bolster or contradict a witness statement or any statements that the suspect may make. Blood evidence can also point the investigator in the direction he or she needs to go to solve the case.”(Brunet, J. 2009) If blood evidence is documented, collected, and stored suitably, it can be presented to a judge or jury several years from the time of the criminal act. Perhaps the most powerful application of blood evidence is the ability to absolutely eliminate a person as a potential suspect in a crime. “As the walk through progresses, the investigators should make sure their hands are occupied by carrying notebooks, flashlights, pens, etc. or by keeping their hands in their pockets.” (Amos, 2011 )
This prevents the investigator from depositing unwanted fingerprints at the crime scene. As a final note on the walk through, the investigators should examine the areas above their heads (ceiling, tree branches, etc.). These areas may yield blood spatters, bullet holes, etc. Once the walk through is completed, the notes must be supplemented with other forms of documentation, such as videotape, photographs, and/or sketches. Videotape can be an excellent medium for documenting bloodstains at a crime scene. If a video camera is available, it is best used after the initial walk through.
This is to record the evidence before any major alterations have occurred at the scene. Videotape provides a perspective on the crime scene layout that cannot be as easily perceived in photographs and sketches. It is a more natural viewing medium to which people can readily relate, especially in demonstrating the structure of the crime scene and how the evidence relates to those structures.
The value of videotaping blood evidence is that the overall relationship of various blood spatters and patterns can be demonstrated. One example of this could be a beating homicide. In this case, videotape can show the overall blood spatter patterns and how these spatters are interred related. The videotape can also show the relationship of the spatters to the various structures at the crime scene.
In cases, where the suspect may have been injured (such as stabbing homicides), the video camera can be used to document any blood trails that may lead away from the scene. If videotaping indoors, the camera can show how the various areas are laid out in relation to each other and how they can be accessed. This is particularly valuable when recording peripheral bloodstains that may be found in other rooms. The high intensity light source can also be used for illuminating the bloodstains to make them more visible on the videotape. Whether a video camera is available or not, it is absolutely essential that still photographs are taken to document the crime scene and any associated blood evidence.
Computer programs are available for sketching crime scenes and blood spatters by inputting certain measurements associated with the scene and the individual spatters. This blood spatter program will then calculate and draw the spatters' points of origin. These programs might come in handy where there are many blood spatters and the points of origin need to be determined. “Scan the crime scene for fingerprints, including handprints and bare footprints.
Remember to check all contact surfaces, such as door and window frames, for any latent fingerprints, which may be partial prints and are not easily visible. Use black or gray powder to dust areas for prints.” (Fielder, M. (2011) Lift the fingerprints from the crime scene, including those from the victim. Fully developed prints can be lifted with adhesive tape over a piece of white card. Chemicals like iodion and silver nitrate can be used to develop latent fingerprints so that they can be photographed. Use a camera with black-and-white film and detachable flash to photograph any fingerprint evidence that cannot be easily lifted.
“Fingerprint evidence has always been reliable, but since DNA has been introduced it has become the evidence of choice when playing a criminal suspect at the crime scene. Everybody has a unique set of DNA, except for identical twins. By using scientific tests, crime scene analysts are able to compare two samples of DNA.” (Geberth, 2006) These usually come from small fragments of the culprit which were left at the crime scene such as hair, blood or saliva. Usually when these tests are done, if the samples match, it is very likely that the suspect was at the scene of the crime.
Once the crime scene has been thoroughly documented and the locations of the evidence noted, then the collection process can begin. The collection process will usually start with the most fragile or most easily lost evidence. Special consideration can also be given to any evidence or objects that need to be moved. Collection can then continue along the crime scene trail or in some other logical manner. Photographs should continue to be taken if the investigator is revealing layers of evidence that were not previously documented because they were obscured.
Most items of evidence will be collected in clean, unused paper containers such as packets, envelopes, and bags. Moist or wet biological evidence (blood, body fluids, plants, etc.) from a crime scene can be collected in clean, unused plastic containers at the scene and transported back to an evidence receiving area if the storage time in sealed plastic is less than two hours and this is done to prevent contamination of other evidence. Once in a secure location, wet evidence, whether packaged in plastic or paper, must be removed and allowed to completely air dry. That evidence can then be repackaged in a new, clean, unused, dry paper container.
“The final method of evidence documentation is the chain of custody form. The chain of custody form is a written record of all evidence transfers from the crime scene to possession of the court or the clerk of court.”(Fielder, 2011) Proper chain of custody thoroughly documents the movement of evidence, the security of the evidence, who had possession of the evidence, and when the evidence was in a person's possession? The chain of custody form must accompany the evidence all the way to its final destination. A copy should also be kept in the case folder.
The following information must be recorded on the form: A description of the evidence and its container; the specific recovery location of the evidence; case numbers; the date and time it was collected; who collected it; whether or not the evidence container was sealed upon transfer to another individual; who received the evidence; the dates and times of any evidence transfers; who delivered the evidence; and the final disposition of the evidence. This is necessary to demonstrate that the evidence was not contaminated in a way to alter the information that the evidence originally contained. It also demonstrates that the original evidence was not planted or changed in some way before its presentation in court.
Before transporting any items of evidence, the investigator should examine the items to determine if there is any loose trace evidence (hairs, fibers, paint chips, etc.) that may be lost in transportation. If there is, then this loose evidence should be collected in a paper packet and placed in an envelope. The envelope should have the required information giving a description and the source of the trace evidence.
The actual item can then be processed and collected. Blood evidence must never be exposed to excessive heat or humidity. If possible, the bloodstained evidence should be refrigerated until it can be transported to the crime lab. The evidence should also be taken to the lab as soon as possible. Package all the collected evidence in envelopes or paper bags. Remember to write the details of where each print was lifted from. The evidence can then be sent to the crime laboratory for analysis. Once in the laboratory, the forensic examiner's signature, the incoming and examination dates, the times, and the department are also logged in. In order to avoid confusion or questionable handling, the evidence should be handled as minimally as possible.
Following opening statements in a homicide trial, the prosecutor presents evidence, consisting of testimony from witnesses and exhibits. In criminal cases, the burden of proof is placed on the prosecution, who must demonstrate that the defendant is guilty before a jury may convict him or her. The evidence collection or recovery step in crime scene processing is the methods, techniques, and procedures used in retrieving evidence. Patience and care are very important at the crime scene. The investigator should take the proper time and care in processing the scene. The work is tedious and time consuming. Teamwork in crime scene investigations is essential. The entire investigation involves many people from different organizations. Each individual has a vital role in the investigation process. Continual communication among all parties involved is paramount.
References: Amos, K. (2011) Investigator at the County Sheriff`s Department, Retrieved February 10, 2011 at 3:00pm during an interview in his office. Brown, J. (2010) Attorney at Law. Retrieved via phone on
February 11, 2011 Brunet, J. (2008) Forensic Science of Bloodstain Pattern Analysis, Retrieved February 11, 2010 From: http://www.suite101.com/content/forensic-bloodstain-pattern-analysis-a167891 Davies, K. (2008). The Murder Book. Upper Saddle River, NJ: Pearson Education Inc Fielder, M. (2011) Chief Deputy at County Sheriff`s Department Retrieved February 10, 2011 at 3:50 pm interview conducted at his office. Geberth, V. (2006) Practical Homicide Investigation: Tactics, Procedures, and Forensic Techniques, Fourth Edition retrieved from Hardin County Library, February 12, 2011