Essentially, the evidence that is gather at a crime scene can make or break a case. Logically, the easier cases to prosecute tend to be the ones that have more physical evidence since the authorities have more ways to link a suspect to a crime. However, even if they find a defendant’s bloody fingerprints all over the scene of a murder, all this compelling evidence is useless in a court of law if the police do not establish a proper chain of custody. Ultimately, each piece of evidence that is gathered must have its own chain of custody to give it creditability when the case reaches the prosecution stage. If gaps are uncovered in the chain of custody of a piece evidence, the presiding judge may decide to throw that particular piece of evidence out of the case, perhaps hurting the prosecutor’s argument against the defendant. Thus, it should be every law enforcement official’s ambition to thoroughly verse himself or herself in the appropriate procedures for establishing solid chains of custody in each case (Byrd, n.d.; Nemeth, 2001, p. 56-59).
The Purpose of Chain of Custody
The first step in appropriately establishing chain of custody is by understanding the fundamental purpose of chain of custody. Essentially, chain of custody is designed to confirm “that the condition of the real evidence being offered has remained basically unchanged-that it is substantially in the same condition as on the date of collection and has not been tampered with or suffered from unwarranted intrusion” (Nemeth, 2001, p. 56). Therefore, the chain of custody is not sufficient unless we have documentation of every individual that was in direct contact with and had custody of the evidence. The chain of custody should remain in tact from the time the evidence was found at the crime scene to the moment it is entered into the criminal proceedings (Byrd, n.d.; Nemeth, 2001, p. 56).
Documenting, Collecting & Preserving Evidence
Furthermore, to learn to establish chain of custody properly, we must understand the necessary steps to documenting, collecting, and preserving pieces of evidence. Once authorities have entered a crime scene, there are a number of steps that must be taken to lend credibility to any evidence retrieved from the premises. First, officials should immediately secure the grounds to prevent any unauthorized persons from entering the scene. Then, the area should be methodically and carefully examined visually to identify possible evidence and to pinpoint more sensitive evidence (such as blood) that should be removed first to avoid contamination or damage of these objects. Such evidence as fingerprints should be high on the priority list during collection since they can easily link a suspect to the location. In the end, the most sensitive and/or crucial evidence should always be collected first, and if other crucial or sensative evidence (such as the bullet and blood posed in one of your questions), all other evidence collection should be paused until this evidence is secured (Schiro, n.d.).
Then, once this visual examination is completed, the entire crime scene and the specific locations of evidence must be carefully documented. Only then should the evidence collection phase begin. Please note that different types of evidence require different documentation, collection, and/or storage procedures to create suitable chain of custody (“Evidence collection guidelines,” n.d.; Schiro, n.d.). For example, let us apply these procedures to our present search. Hypothetically, let us say we discovered three types of evidence: (1) a set of documents outlining cocaine transactions, (2) a package of white powder, which field tests indicate is cocaine, and (3) a firearm. Of course, we are required to establish a chain of custody for both of these for the evidence to be admissable once this case reaches court. However, each has its own required collection procedure to protect it from contamination and/or tampering. First, if authorities feel they have found questionable documents at a crime scene, they must ensure they collect all questionable documents, so they can be compared and examined at a later time. Also, every effort should be made to avoid changing the questionable documents in any way (i.e., adding new creases or unnecessary marks). Finally, questionable documents ideally should be placed in sealed protective envelopes (plastic or cellophane). The container of cocaine, though, is typically collected in paper envelopes and must be sealed thoroughly since its consistency could cause leaking or spilling (“Evidence collection guidelines,” n.d.). Finally, firearms found at a crime scene warrant much more caution than the previous two types of evidence. Ultimately, when an agent discovers a firearm, he or she normally cannot know whether or not it is loaded. Therefore, the safety of the agent is more important than the preservation of the evidence. Each firearm must be made safe before it can be moved from the scene (i.e., removing the bullets), but every action and/or test used to ensure safety must be carefully recorded to create proper chain of custody. Lastly, any firearm should be sealed in a paper bag or envelop separately from any ammunition or magazines (Schiro, n.d.).
Finally, it is just as important to ensure that every piece of evidence is properly labeled so it can be identified later, not only for the benefit of the investigation but also to establish chain of custody. Some types of evidence require a direct label, while others can be labeled using a tag. However, whatever labelling method is used, each piece of evidence should be marked with the following information: (1) a description of the piece of evidence, (2) the case number, (3) the date and location it was collected, (4) the individual that gathered the item, and (4) another other identifying information (i.e., brand of product). Also, the evidence package of each piece of evidence should be marked with similar information that corresponds to the information that appears on the objects themselves (Byrd, n.d.). Once this is complete and all evidence is removed from the scene, all evidence should be transported as soon possible in sealed containers to the crime lab or to a secure storage location to maintain chain of custody and to avoid contamination or degradation of evidence. Some types of evidence require immediate attention (i.e., bloodied clothes need dried to prevent mildew or mold) or special storage (i.e., blood samples require refrigeration); therefore, it is recommended that they be taken directly to the lab or storage facility. Nevertheless, types of evidence such as questioned documents are often permitted to be shipped using registered or certified mail. In the end, every law enforcement official must familiarize himself or herself with the standard evidence procedures for his or her own agency to understand exactly what to do to establish and maintain chain of custody (“Evidence collection guidelines,” n.d.).
References:
Byrd, M. (n.d.). Proper tagging and labeling of evidence for later identification. Retrieved April 28, 2008, fromhttp://www.crime-scene-investigator.net/tagging.html
Evidence collection guidelines. (n.d.). April 28, 2008, from http://www.crime-scene-investigator.net/collect.html
Nemeth, C. P. (2001). Law and evidence: A primer for criminal justice, criminology, law, and legal studies. Upper Saddle River, NJ: Prentice Hall.
Schiro, G. (n.d.). Part 3: Collection and preservation of evidence. Retrieved April 28, 2008, from http://www.crime-scene-investigator.net/evidenc3.html
