When the police collect and submit physical evidence in a drug case, investigators and technicians must follow proper protocols to maintain the integrity of the evidence. Lapses or mistakes in the chain of custody of evidence can call into question the reliability and admissibility of that evidence, which may help your defense.
There are a few things you should understand about the chain of custody and its role in your case.
Chain of custody record
A clear, unbroken chain of custody shows who has handled evidence, when they handled it, and what occurred at each step. Any gaps in documenting the chain of custody can raise questions. Each piece of evidence should include a chain of custody form. That form includes all of the relevant details to track its movement and handling.
Any weakness in the chain of custody creates vulnerabilities for tampering, replacement, contamination or alteration of evidence. For example, if the seal on a piece of evidence appears broken or if the labeling or documentation does not match the original evidence collection, it can weaken the integrity of the evidence. In drug cases, this is easier than you think, especially with misplacement of drug evidence and cross-contamination risks.
Significant delays in analyzing or testing evidence without reasonable explanation can also weaken the evidentiary value. For instance, if a blood sample or an assumed illicit substance sits untested for weeks or months before testing, it raises concerns over proper storage and the reliability of any test results.
Carefully examining the chain of custody can provide opportunities for the defense to challenge the admissibility and evidentiary weight of physical evidence.