Testing DNA on a firearm can involve several steps during a criminal case. It's something that helps contribute important evidence for a trial. Here's the thing: not many people actually know how DNA is tested on guns to make this possible. 

When a firearm is evidence for an investigation, investigators may consider more than just the fingerprints and ballistics of the firearm. A gun can also contain biological material that may provide a DNA profile to match the person who is on trial. Finding DNA on a firearm does not immediately establish who had the firearm or who fired it if that was a part of the crime.

For defendants facing a firearm-related criminal charge in Buffalo and Western New York, understanding how firearm DNA testing works can help educate you on what forensic evidence can and cannot show during the trial. It's our job to make sure you know this and are ready for it if you are on trial and you need our help for your defense. 

In this blog, we will explain how law enforcement tests for DNA on guns in New York State when preparing for a criminal trial.

Recovering the Firearm From the Crime Scene

The process of testing for DNA begins when law enforcement recovers the firearm from the crime scene. This helps to preserve the firearm and send it over for laboratory examination. New York State works to have evidence documentation, collection, and preservation as important responsibilities of its forensic identification personnel.

This stage in the process matters because a firearm may contain several different types of evidence. Investigators may want to preserve potential DNA and latent fingerprints while also conducting firearms examinations and, when appropriate, test-firing the firearm for ballistic comparison to other similar firearms. New York State addresses preserving potential DNA and latent-print evidence before firearms-related processing, and that's important to keep in mind.

Where the DNA Testing Process Occurs

In New York State, firearm evidence may be submitted to an accredited public forensic laboratory for examination. The New York State Crime Laboratory System (CLS) provides forensic services in biological sciences, firearms, forensic identification, and other disciplines.

Western New York also has access to public forensic laboratory resources, including the Erie County Department of Central Police Services Forensic Laboratory, which participates in the state's DNA system. Depending on the investigating agency, the evidence, and the circumstances of the case, a specific laboratory and testing protocol will be assigned to a case. This is one of the primary locations here in WNY that will get that responsibility. 

Breaking Down the DNA You Find on a Gun

In an investigation, people are not always going to analyze every square inch of a firearm. They may target areas that are likely to have been touched, such as the trigger, trigger guard, grip, slide, and safety.

A recent New York State court decision (People v. Morales in 2024) illustrates how this can work. In that case, swabs were collected from several areas of a firearm, including the ones that we just specified. The goal is to collect biological material that may contain cells suitable for DNA analysis, and this case helps outline that. A swab, however, is not itself proof that a usable DNA profile will be obtained.

Testing and Comparing the DNA in the Laboratory

When DNA evidence reaches the laboratory, forensic analysts determine whether biological material is present and if it is suitable to be used. New York State Police describes forensic serology as the identification, collection, and preservation of biological materials that may be used in DNA analysis. Forensic DNA analysis develops DNA profiles from biological evidence for comparison. 

Sometimes the result is more straightforward than you think. Other times, the sample may contain DNA from multiple people instead of one. These are known as mixtures, and interpreting a mixture can be considerably more complicated than interpreting a single-source profile.

If a suitable DNA profile is developed, it may be compared with a known reference sample from a defendant, suspect, victim, or another relevant individual, and in appropriate circumstances may be searched through applicable DNA databases. A comparison can potentially include either the defendant, a victim, a new suspect, or another individual whose DNA is relevant to the investigation.

Importantly, the presence of someone's DNA on a firearm does not necessarily establish when the DNA was deposited or exactly how the person came into contact with the firearm. DNA evidence has to be considered alongside the other evidence in the case; it's not just one piece to the puzzle that explains it all.

The CODIS and DNA Databank

There is also what's called the Combined DNA Index System (CODIS). It's a database that's used by the FBI, and it uses forensic science and computer software to store and compare DNA profiles electronically across local, state, and federal law enforcement agencies.

New York maintains a State DNA Identification Index, while suitable forensic profiles may also be searched through CODIS, the FBI-administered national system. This system can generate investigative leads when profiles correspond with each other. A database hit is an investigative lead, which doesn't mean it's a full explanation of the circumstances surrounding the DNA's presence.

How a Criminal Defense Attorney Helps

When it comes to the defense, the importance of criminal cases like these that relate to firearms goes beyond what the final test results say about the DNA that was analyzed. We, as defense attorneys, will examine every single aspect of this when it comes to the evidence and interpret the results to make a good defense on your part.

New York State's automatic discovery statute requires prosecutors to disclose specified evidence and permits defendants to inspect, copy, photograph, and test discoverable material in the prosecution's possession. Courts can also issue orders concerning preservation and access to evidence. We will make sure these rules are all established for you when it comes time to make our defense. If you have any questions or are in need of legal representation, give us a call or reach out through our contact form.

Criminal Defense FAQ

Can the DNA on a gun prove who fired it? 

DNA found on a firearm may help identify a person who handled or came into contact with the firearm, but generally speaking, it does not establish who fired the weapon or how the person came into contact with it. The evidence can involve a mixture of multiple people's DNA. In a New York criminal case, firearm DNA evidence should therefore be considered alongside other evidence, such as fingerprints, ballistics, eyewitness testimony, and other forensic evidence.

DISCLAIMER: PAST RESULTS DO NOT GUARANTEE FUTURE RESULTS. THIS IS NOT LEGAL ADVICE. DANIEL DUBOIS AND ANY DUBOIS LAW ATTORNEYS ARE NOT YOUR ATTORNEYS UNLESS RETAINED. INFORMATION SHARED HERE IS FOR INFORMATIONAL AND EDUCATIONAL PURPOSES ONLY. EACH CASE IS UNIQUE AND IS DECIDED BASED ON ITS OWN FACTS AND MERITS AND CANNOT BE COMPARED TO OTHER CASES WHICH MAY HAVE HAD DIFFERENT FACTS AND CIRCUMSTANCES.