The Importance of Chain of Custody

In any criminal trial, it is important for the prosecution to be able to establish the chain of custody. Chain of custody is the “movement and location of physical evidence from the time it is obtained to the time it is presented in court.” This issue is particularly prominent in the world of drunk driving charges that rely on a blood test to show that the individual was intoxicated while driving.

Judges who preside over bench trials and jurors who are present at jury trials must decide cases based on the evidence presented to them in court. The evidence used in court cannot be anything that someone pulled out of an old closet or found under her bed. It must be certified before it can be admitted as evidence. This means that if the defense or the prosecution considers evidence to be somewhat dubious or suspicious, the party presenting the evidence can be compelled to say how and where they obtained the evidence.

Prosecutors in various districts have found themselves, in recent years, in the dilemma of not being able to say exactly what happened to a piece of evidence between the crime scene and the courtroom. This presents a problem because, without establishing the chain, it is very difficult to say that the piece is the same as the one taken from the actual crime scene or that nothing has happened to it to manipulate the evidence between the crime and the trial. . The care given to the evidence is also crucial.

When the chain of custody cannot be shown for the entire period between the crime and the actual trial, there can be serious issues as to whether the evidence is valid. Also, without chain tracking, there is really no certification of evidence, as there are loopholes where things could have been changed or mishandled.

In drunk driving cases, failing to prove chain of custody on a blood sample which is the primary piece of evidence used to prove the case, the blood sample may be thrown out and the entire case rendered useless. In the event that no one is sure where the sample was for a period before or after the test, the blood may have been switched with some other sample, mistested, incorrectly tested, or any of a number of other things that question the integrity of the evidence.