The Texas Department of Public Safety’s crime labs across the state opened their doors to the public last week, offering a glimpse into the world of forensic science through tours of their facilities and demonstrations of their areas of expertise.
The Dallas Express visited the DPS crime lab in Garland, one of two facilities — the other is in Tyler — serving the North Texas area. The beige 54,000-square-foot four-story building, nearly hidden from the view of passersby on IH 30, offers no clue about the important work going on inside.
The facility is where district attorneys, police, sheriffs, and fire departments from multiple North Texas counties send evidence for DNA analysis, trace evidence, latent prints, drug testing, forensic firearm examination, toxicology testing, and other specialized services.
The Garland lab assists law enforcement with more than 21,000 cases per year, each of which may involve many pieces of evidence.
As of September 1, evidence must be submitted in person by appointment only, rather than through the mail. Submissions must also adhere to strict packaging and security requirements to maintain the integrity of the evidence. Each piece of evidence is assigned a barcode, which is used to track the chain of custody at the lab. Evidence that is pending analysis or awaiting return is stored in a secure vault, which can only be accessed when two authorized personnel members scan their security badges together.
The DNA Analysis division of the Garland crime lab accepts evidence from 40 counties in North and Northeast Texas. The lab maintains a 90-day turnaround on sexual assault cases. DNA can be extracted from samples of blood, semen, saliva, sweat, skin cells, and hair. The lab also performs Y-STR analysis, which can be used to identify male individuals in crime scene investigations.
The results from the testing are entered into the Combined DNA Index System (CODIS), a national database maintained by the FBI, and are often helpful in linking a victim or suspect to the evidence, eliminating a suspect, or linking one crime scene to another.
The Latents division is where fingerprints, palm prints, and footprints are retrieved and photographed for comparison. Different methods are used to extract prints, depending on whether the piece of evidence is porous or non-porous, and whether it is dark or light in color. The prints are entered into a national database where analysts can search for a match.
In the Trace Evidence division, testing can help identify hair and fiber samples, paints, polymers, tape residue, paint chips, and a wide range of other substances. Analysts may be asked to test for product tampering or match shoe or tire impressions by comparing wear patterns. The team has a shelf full of reference books to aid in identifying different brands, models, and specific product characteristics, including one that provides an objective reading of colors.
In the Firearms division, analysts compare bullets to bullets, bullets to cartridge cases, and bullets to guns. The bullet and cartridge case toolmark data are entered into a database to aid in identifying firearms and linking evidence in criminal investigations. The lab has an indoor firing range, which includes a water tank and a cotton box, both of which are used to capture and recover the fired test bullets for comparison.
The team also has a process for restoring serial numbers on weapons when the engraved number has been destroyed.
The Firearms division also specializes in identifying other types of tool marks, such as those made by bolt cutters on locks, for example. The harder object always leaves a mark on the softer object. Since tools can be used in various ways, the forensic scientist must consider every possibility when testing these tools.
The Seized Drug division identifies unknown drug substances using various tests and types of equipment. Methamphetamines and coke were the most commonly seized drugs seen in the lab, followed by fentanyl.
The Toxicology division is one of the busiest divisions in the lab, and the Garland division is one of the busiest in the state, handling 8,554 cases last year. Forensic scientists from Toxicology are called to testify in court more than any other division. Scientists “analyze biological specimens to detect alcohol, volatiles, and/or drugs in investigations related to driving while intoxicated (DWI), sexual assault, and homicide,” Texas DPS states on its website.
Free tours of the Texas DPS crime labs were offered during National Forensic Science Week, highlighting the important work that these forensic experts do that is often unseen and unnoticed by the public.
“The men and women of the Crime Laboratory Division work tirelessly behind the scenes to provide answers, support justice, and ultimately protect and serve the people of Texas every day,” said Crime Laboratory Chief Brady Mills. “Their work is vital to the operations of law enforcement agencies across this state, and we are proud to be able to assist our partners in this way.”