In any criminal trial, it is important that the prosecution can 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 problem is particularly important in the world of drunk driving charges that rely on a blood test to show that the person was drunk while driving.

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

Prosecutors in various districts have, in recent years, found themselves in the dilemma of not being able to tell exactly what happened with a little bit 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 alter the evidence between the crime and the trial. . The care offered 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 problems as to whether the evidence is valid. Also, without chain tracking, there is not really a certification of the evidence, as there are loopholes where things could have been changed or mishandled.

In drunk driving cases, by not being able to prove chain of custody on a blood sample which is the main test used to prove the case, the blood sample can be thrown away and the whole case will be 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 swapped for another sample, not tested correctly, wrong test performed, or any of a number of other things that all question the integrity of the evidence.