Preservation of Evidence in Criminal CasesIt is the duty of law enforcement officials and prosecutors to preserve specific types of evidence obtained during a criminal investigation and trial to protect a defendant’s rights. Once evidence has begun to be collected by a state agency in California for a criminal investigation, it must immediately be preserved as evidence. The 6th and 14th Amendments to the United States Constitution give a defendant the right to a due process and a fair trial. It is the responsibility of law enforcement officials and prosecutors to disclose the evidence it plans to use against the defendant during the trial. It also is the duty of law enforcement officials and prosecutors to disclose evidence that would benefit the defense.

Evidence That Must be Preserved
All evidence obtained by law enforcement officials does not have to be preserved. However, all evidence that may play a role in the suspect’s defense should be kept safe. “Material evidence” is evidence related to a part of the defendant’s case, and “exculpatory evidence” is evidence that likely could clear the defendant of guilt. The circumstances surrounding a case dictate whether evidence is material or exculpatory. Alibi evidence, for example, could be both material and exculpatory, which include statements by witnesses placing the defendant somewhere other than the crime scene. Typical evidence that must be preserved include: evidence obtained at the crime scene; tape recordings and videos; notes taken during an investigation; and emergency call recordings.

The Importance of Preserving DNA Evidence
Preserving evidence allows the ability for one to be proven innocent. Evidence containing DNA especially is important, as it can exonerate a defendant who is innocent. It is this biological evidence that is best used to to prove someone’s innocence or someone’s guilt upon review of a case. DNA evidence that has been preserved also has been used to solve cases that once were closed. Preserving DNA evidence preserves the ability to prove innocence, plain and simple. It must be done.

What if the Evidence Was Destroyed?
Unfortunately, it often is the burden of a defendant to prove that evidence was not property preserved and this compromised his or her rights to due process and a fair trial. A defendant must prove that the evidence lost was material evidence or possibly exculpatory evidence. To establish that the evidence was not preserved, a defendant must show that the law enforcement officers had a reason to destroy it, for example. It also is the responsibility of the defendant, and his or her criminal defense attorney, to prove the evidence was destroyed in “bad faith.” This means that the officials handled the evidence with negligence and acted deceitful, willful and with malicious intent. For example, if a police department simply threw away the fingerprint sample that showed it could not have been the defendant who did the crime, this would be an example of “bad faith,” as the evidence was not preserved.