Free Trial

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56 Chapter 3 · Preparing for Prosecution and Testifying hold yourself out as an all-around computer expert, you are begging defense counsel to ask you about computer chip design or the intricacies of HTML programming. Jurors like plainspoken witnesses who testify in simple terms about what they said and did. Don't let the technical tools that you may have used to discover evidence confuse the jury: you are simply there to tell them what you did and what you saw. Chain of Custody In order for any evidence to be admitted at trial, the proponent, or the party offering the evidence to the court, must authenticate the evidence.That, is the proponent must establish that the evidence actually is what it purports to be. What this means as a practical matter can best be explained by way of example. In a murder case in which the defendant was stabbed to death, a bloody knife might be powerful evidence. On the other hand, unless the bloody knife was actually the one that was found at the scene of the crime, then the evidence is entirely irrelevant and useless for the jury to consider. In this type of a case, how is the evidence authenticated? The answer is simple:The first investigator who discovered the knife would testify that the knife being offered into evidence by the prosecutor is the same one that was found at the murder scene, in the same condition as when it was discovered. If the investigator couldn't remember exactly what the knife looked like at the scene, the investigator could refresh his memory by looking at a photo- graph of the knife at the scene. Any type of evidence that is unique and readily identifiable may be authenticated in this way. Some types of evidence, however, are trickier to authenticate. For example, in a case in which investigators discovered three ounces of cocaine in a shoebox at the defendant's house, how could an investigator honestly say at trial that the bag of nondescript white powder that the prosecutor wants to offer into evidence is actually the cocaine that the investigator discovered in the defendant's house? In legal terms, how can the proponent of the evidence authenticate that the evidence is what it purports to be? In these types of cases, investigators usually must resort to authenticating the evidence by estab- lishing the "chain of custody" of the evidence.