Every law enforcement official and prosecutor must preserve specific types of evidence in order to protect the 6th and 14th constitutional ammendment rights of defendants. All defendants have a right to due process and a fair trial. Evidence is highly important in prosecuting as well as exonerating innocent defendants.
Physical evidence must be collected in a timely manner. If enough time passes, this evidence can become lost, tainted or completely unavailable.
There are three different types of evidence that can be used in a defendant’s case.
- Material evidence – evidence that is related to a part of the defendant’s case
- Exculpatory evidence – evidence that could clear a defendant of guilt
- Alibi evidence – either material or exculpatory evidence that can consist of eyewitness statements placing the defendant somewhere other than the crime scene at the time of the incident
DNA evidence is the most important form of evidence that must be preserved. This type of evidence often exonerates defendants who are innocent, and it can also be used to solve cases that were once cold.
Besides DNA, other evidence that should not be destroyed include emergency call recordings, videotapes, tape recordings, investigative notes and crime scene evidence.
If evidence has been destroyed, it’s usually the burden of the defendant to prove it was not preserved properly. They also must prove that the evidence was handled in “bad faith,” meaning it was destroyed on purpose.
According to NOLO, there are several people besides police officers who must preserve evidence including prosecutors, the Attorney General, and individuals from local, state and investigative agencies.