Firearms & Toolmark Identification

Firearms & Tool Mark Identification

The Montgomery County Sheriff’s Office (MCSO) offers firearms and related analysis to assist law enforcement agencies and the judicial system in Montgomery County, Texas.  It is the mission of the Firearms Section to produce a quality work product in an efficient time period while maintaining a non-biased and professional manner during all examinations and interactions with all personnel (external and internal).

The Firearms Section utilizes forensic comparison microscopes, digital measuring software, and digital cameras to compare and document evidentiary items.

The following services are offered: 

Firearms Analysis
1. Comparison of suspect firearms to projectiles, bullets, and cartridge cases collected at crime scenes.
2. Identification of bullets (i.e. caliber, make, and potential list of firearms if no firearm is collected).
3. Analysis to determine the condition of the firearms (safeties, trigger pull force, and general operability of the firearm). 


Serial Number Restoration*
1. Analysis to determine and restore serial numbers on items of evidence that have been altered or obliterated.

2. If a serial number is restored, that number can be searched in E-trace; which is a web-based application that allows firearms to be traced via the National Tracing Center of the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF).  This may allow a stolen firearm to be returned to its legal owner.

*Work performed in Serial Number Restoration is not covered by accreditation.

Firearms Database Services
MCSO is a partner in the National Integrated Ballistic Information Network (NIBIN) which is sponsored by the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF). NIBIN allows for the capture and comparison of ballistic evidence (fired cartridge cases) to provide actionable investigative leads in a timely manner. The backbone of NIBIN is the Integrated Ballistic Identification System (IBIS) which enables the sharing and comparison of millions of firearm exhibit images across the US.  It provides investigators the ability to compare their ballistics evidence against evidence from other firearm-related crimes on a national, regional, and local level.


Firearms Examiner and FATM Technical Leader Pat Bui is a member of the Association of Firearm and Tool Mark Examiners (AFTE) and is certified in Firearm Evidence Examination and Identification through this organization.

Please contact Firearms Examiner Patricia Bui for any questions regarding firearms evidence and analysis at or (936) 760-5878.


The Firearms and Tool Mark Section within the Montgomery County Sheriff’s Office Crime Laboratory is an accredited Forensic Inspection Agency through ANAB ANSI National Accreditation Board under ISO/IEC 17020 / ANAB AR 3120 and all examiners are licensed through the Texas Forensic Science Commission. ANAB Symbol - Forensic Inspection