What is “Chain of Custody”?

Posted by Michael E. Lyons | Sep 12, 2019 | 0 Comments

In criminal court cases, both inside the military and in civilian courtrooms, there are certain procedures the prosecution must follow to admit physical evidence in a trial. This means that for every exhibit of physical evidence, the prosecution should have a carefully maintained record of where that evidence came from, where and how it was stored, and who came in contact with it. This record is called the “chain of custody,” and it can make or break a criminal prosecution. A well-kept chain of custody helps ensure a fair trial. A messy chain of custody can cause a case to fall apart.

At Patriots Law Group, we understand the importance of chain of custody. As experienced defense attorneys, we identify weak spots in the prosecution's case to give our clients the best defense possible. If you are involved in a criminal case with physical evidence, it is critical to have an attorney represent you who understands the concept of chain of custody and why it is so important – and can explain it to a jury in a way that makes sense.

What is admissible evidence?

To prove someone committed a crime, a prosecutor needs evidence. Individual pieces of physical evidence are known as exhibits, and physical evidence must follow a strict chain of custody to guarantee that the evidence has not been altered. For example, an exhibit could be illegal drugs in a possession case, DNA from a rape kit, or the weapon used in an assault case. The jury can only consider evidence that is admissible, which may depend on the completeness and accuracy of the chain of custody.

When is evidence inadmissible?

Most criminal prosecutors build cases against a defendant based on evidence collected by police officers or other authorities. This evidence is sometimes mishandled and may subject the chain of custody to scrutiny. This is where we go to work to dismantle the prosecution's case by asking the court to rule that mishandled evidence be suppressed. If we can't make that happen, we will be sure to painstakingly point out all the problems with the prosecution's evidence, pointing out to the jury why it shouldn't be trusted.  In short, inadmissible evidence cannot be put forward in a court case, and admissible evidence that has a faulty chain of custody can be challenged. This means that even if the prosecution has the murder weapon in hand, it may not be able to be used as evidence if the authorities did not handle it correctly.

What does “chain of custody” look like?   

Let's say that a young lady is accused of driving while under the influence of cocaine. To build their case, the prosecution submits an interesting piece of physical evidence: a plastic baggie with cocaine residue found in the parking lot of the apartment complex the young lady left just minutes before she was pulled over (with her DNA on it). In order to use this piece of evidence, the prosecution must show the chain of custody from the time it was seized to the time it gets to trial.

The baggie should have been collected by an officer wearing gloves, and it should be placed in an evidence bag alone so there is no cross-contamination.  Next, there should be a log of who possesses that evidence bag that should be signed off every time it changes hands or is placed in or removed from evidence storage.  Then, the lab that tests it to determine that it does in fact contain cocaine residue and the DNA of the accused should make detailed notes of each step that was taken, certifications of their machines and personnel, and be able to describe the ways in which they combat cross contamination or transfer, and ensure the accuracy of the tests and results.

For example, if the defendant's cigarette was also found in the parking lot and was placed in the same bag, maybe all the prosecution can really prove is that she smoked that cigarette because the DNA from that could have been transferred to the baggie.  OR, maybe that baggie never had cocaine in it, but the machine used to test for that had recently tested something else for cocaine and hadn't been cleaned or calibrated properly.

There are many ways to attack chain of custody and weaken the prosecution's case against you – make sure you have an attorney on your side that is experienced in finding these issues and highlighting them for a judge or a jury.

What happens if crucial exhibits are kept out of evidence?

If it is determined that the chain of custody was broken sometime between the event and the trial itself, that evidence may be deemed inadmissible. In our example above, if there is enough doubt on the accuracy of the testing done on that baggie and there is even a chance it may be suppressed, then the prosecutors may be worried enough about the strength of their case to offer a great deal – or maybe even drop the charges altogether.

To that end, it is critical to work with attorneys who understand the importance of chain of custody. At Patriots Law Group, we have built successful defenses based on chain of custody deficiencies– and we want to do the same for you. Call Patriots Law Group at 301-952-9000 to schedule a consultation.

 DISCLAIMER:  The information above is for general informational purposes only.  No attorney-client relationship is intended or created by this information.  Each individual situation is different and therefore a formal in-person consultation is necessary before any specific advice may be relied upon as appropriate and accurate for a given situation. Please call Patriots Law Group at 301-952-9000 to set up a consultation if you wish to obtain specific legal advice you may rely upon. We serve clients anywhere in the world, with in-person consultations available at our Suitland, MD office — right next to Andrews Air Force Base — for clients in Maryland, Virginia, and Washington, D.C.

About the Author

Michael E. Lyons

“As a veteran, I bring my core values of service, integrity, and excellence to every client, every case, every time.” Background: Michael E. Lyons (“Mike”) handles cases in Maryland and Washington D.C. fr...


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