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By: Ken Francis, A.I.A., and Harold Messler  
Issue: August/September 2005

THE ST. LOUIS POLICE DEPARTMENT’S NEW FORENSIC LAB IS A TEXTBOOK CASE OF A LAB THAT IS SAFE, SECURE, AND PREPARED FOR “WHAT COMES NEXT” IN SOLVING CRIMES.

Back in 1934, Dr. Rutherford B.H. Gradwohl opened the doors of the St. Louis Police Department’s first forensics laboratory, a small, nondescript space on the third floor of police headquarters.

For the previous 30 years, the fingerprint had been the most powerful tool in the police’s forensic toolbox. About this same time, however, a new breed of scientific crime fighter was emerging. Armed with microscopes and chemical tests, these professionals were trained in serological testing, toxicology and drug analysis. Scientific investigations had just begun to gain acceptance in the nation’s courtrooms.

Since the dawn of this new era of “scientific crime detection” — forensic science has advanced in ways that Dr. Gradwohl could have barely imagined. And so have the forensic labs where criminalists today perform their work.

The St. Louis Police Department’s new $8.5 million forensic laboratory – one of only two accredited forensic labs in the State of Missouri — is a prime example.

Each drug chemist's U-shaped work station is equipped with its own chemical fume hood, snorkels, LIMS terminals, and other lab equipment needed for color and crystal tests, infrared spectrophotometry and gas chromatography/mass spectroscopy

Designed by a joint venture of Burns & McDonnell and ERM Technologies, the three-story, 40,000-square-foot new lab that opened this spring has been called a “criminalist’s dream,” with design features that enhance productivity and crime-solving effectiveness, while improving security and helping prevent cross contamination of evidence in the process.

The lab also provided some much-needed breathing space for the SLPD’s 40-person forensics staff, which had grown accustomed to operating in 9,600 square feet of converted space that lacked the ventilation, humidity controls, and other special systems preferred for laboratory work.

Located adjacent to the existing police headquarters building on the site of a former parking lot in downtown St. Louis, the new lab more than triples the department’s crime lab space. The larger facility not only enhances the department’s ability to test blood, DNA, drug traces, firearms, and other crime scene evidence, its design has been future-proofed to support crime-solving technologies “still in the imagination,” according to St. Louis Police Chief Joe Mokwa.

We’ll give you a look inside.

“First, do no harm”
If there were a Hippocratic Oath for criminalists, the first tenet would probably be: “First, do no harm.” The first obligation of criminalists, in other words, is to do everything they can to protect the evidence entrusted to them. Proper documentation and handling are critical if evidence is to be admissible in court. That means, among other things, establishing and preserving the “chain of custody” for all evidentiary material entering or leaving the lab.

At the St. Louis Police’s Forensic Lab, that chain begins in the lab’s secure, first-level garage. Two vehicle processing bays there are used to conduct analysis on crime scene vehicles. Enclosed and fully equipped – including snorkling vents to draw fumes from the space — these bays are one of the only places in the SLPD’s forensic lab where experts in DNA, fingerprinting, and other forensic sciences “go to the evidence” for testing and analysis, rather than have it come to them.

Virtually all of the remaining evidence enters the first-floor garage in the SLPD’s Evidence Technician Unit (ETU) vans. From these vans, evidentiary materials are taken in a secure, dedicated elevator directly to the lab’s third-floor Evidence Receiving Area for check-in, bar-coding, and processing.

Once they arrive on the third floor, a bullet proof glass window meets officers entering the Evidence Receiving lobby. On the other side of the window are evidence clerks, ready to receive smaller items through small slots in the glass. The bulletproof panel, incidentally, is not designed so much to protect against an assault on the lab. Rather, it’s primarily there to protect workers in the event of a weapon’s accidental discharge as it is checked in.

Larger evidentiary items, meanwhile, are submitted via a larger pass-through evidence bay with locked doors on both sides. After the outer door is unlocked, an ETU officer places a bag of evidence inside the bay and relocks the door. Because only one door is allowed open at a given time, the clerk waits till the outer door is locked before unlocking the inner door to receive and tag the evidence and enter it into the SLPD’s Laboratory Information Management System.

Once checked in, evidence is placed in a secure storage room or, in the case of drugs, in a climate-controlled drug vault adjacent to the second floor chemistry lab until it is ready to be processed.

Biosafety cabinets in a biology prep area of the St. Louis Police Department's new forensics lab are used to dry bloody or wet clothing. This prep area, which also includes refrigerators and freezers for interim storage and a high purity water system, adjoins four biology screening labs.

ID-ing Crack Cocaine in Minutes
What happens next depends on the evidence to be tested. If it is drug-related, chances are good that the evidence will make its way fairly quickly to the lab’s second-floor chemistry unit, where all suspected illegal or controlled substances are sent for testing and analysis.

This happens quickly because the St. Louis Police Department has established a protocol for analyzing all drugs within 20 hours of an arrest. That’s a particularly aggressive timetable, considering that the average turnaround time for drug testing in most parts of the country ranges from 14 to 30 days.

The need for rapid turnaround played a key role in the chemistry unit’s design. While many labs purposely segregate each individual lab function, the SLPD’s chemistry unit was designed so that all four of the scientists there have everything they need to positively identify crack cocaine – and many other drugs – within minutes.

To make that possible, each scientist’s work station is equipped with its own fume hood, complete with a sink on one side and lab equipment on the other, including everything needed for color and crystal tests; infrared spectrophotometry and gas chromatography/mass spectroscopy.

Each examiner’s u-shaped module also includes a data terminal where, using the department’s Laboratory Information Management System, they can swipe the bar code on each bag of evidence and access up-to-the-minute information on its background and status. Using video microscopes, examiners can capture microscopic images of the evidence for storage in the LIMS system.

Current crime trends – namely, the dramatic rise in methamphetamine production — also impacted the chemistry unit’s design. Because of the dangerous, explosive nature of the solvents involved in meth production, designers included an explosion-proof fume hood in the chemistry lab that is used primarily to test suspected meth.

Used an average of 25 times a day, the Firearms Unit's firing range was designed with a much higher-than-average air exchange rate to ensure smoke from the firearms is removed from the space quickly.	Because it is designed to maintain negative air pressure, the Post Amplification Lab, where DNA is amplified for analysis, is accessible only by an electronic air lock.

Preventing Contamination of DNA Evidence
At every step in the evidence trail, the designers’ goal was to create an environment that prevented cross-contamination – from sources both inside and outside the lab. At few locations were their efforts more deliberate than in the second-floor DNA/Biosciences Unit, where scientists employ a full spectrum of modern forensic DNA identification technologies to analyze body fluids and tissues in hopes of identifying perpetrators of violent crimes.

For this kind of testing, in particular, scientists have several potential contamination concerns. First, they don’t want skin or dust particles or other evidence to inadvertently “blow in” through the HVAC system and compromise the sample. Designers prevent that from happening through careful regulation of air flow and pressure. Within the DNA labs themselves, for example, air flow is regulated so that air from earlier in the evidence stream isn’t drawn down into their space.

In addition, everyone – and everything – entering or leaving the trace rooms and DNA labs must first pass through an electronic air lock. Even the trash removed from the Post Amplification Lab, where DNA is amplified for analysis, is taken into a small chamber and passed through an autoclave to help prevent contamination.

Evidence can be compromised by human error as it moves through the evidence stream, such as when a sample is moved from one container to another. The DNA Unit’s large pre-amplification lab, where samples are prepared for testing, is designed to help prevent such errors. The hoods on the lab’s two six-foot biosafety cabinets are both large enough to accommodate two persons working side by side – an examiner and a reader whose job is to verify the transfer of material. This two-person approach, in fact, is now part of the ASCLD/LAB DNA quality control procedure.

Evidence can be cross-contaminated in many other ways as well. For example, it is possible for hair or blood removed from one location to become contaminated by similar samples taken at an earlier time. To eliminate that threat, the biology lab was designed to include four trace exam rooms, where evidence can be sorted either by place or by time. Video cameras installed in two of the trace rooms can be positioned directly on the evidence, so case homicide officers can view the items on a conference room’s plasma screen – without contacting the evidence itself.

Environmental conditions can also compromise evidence. To protect its efficacy, DNA evidence, for example, is stored in -70° C freezers in climate-controlled rooms. If a technician accidentally leaves a freezer door open late on a Saturday night, the department needs to know it.

In fact, the temperature, pressure, and humidity and energy needs range widely throughout the building, creating the need for sophisticated mechanical systems and an automated building management system to monitor and control them. Each lab is zone-controlled for temperature. The drug vault and firearms unit have their own exhaust systems. A highly efficient stroboscobic fan system exhausts fumes from chemical hoods in the laboratories. Emergency energy systems are in place in the event of a power outage.

Not all evidence contamination, unfortunately, is purely accidental. To help prevent evidence tampering, security in the SLPD’s Forensics Lab is particularly tight.
Card reader systems, for example, are in place to limit access throughout the building. Card access is required at the entry doors to the main building and elevators, as well as to individual lab units. Security cameras monitor activities at various areas inside and outside of the building. Motion detectors are located in the drug vault and other sensitive spaces throughout the building.

All of these operations – temperature, humidity, air pressure, security — are monitored from a central building management center located on the building’s first floor. This computer-based system sounds an alarm when any of these systems is outside of its programmed range. It then pages designated personnel until the problem is resolved. It’s from this location that the building manager also monitors the lab’s vacuum, air compression, water, and lab gas systems, all of which are stored on the ground floor. As the supply is depleted, the system automatically switches over to a new tank.

Other Unique Design Considerations
Contamination isn’t the only thing designers must consider when designing a forensic lab’s mechanical systems. There are other unique considerations as well. Few other kinds of laboratories, for example, contain 40-foot indoor shooting ranges. Used an average of 25 times a day, the firing range is a key component in the SLPD’s Forensic Lab’s Firearms Unit, which focuses, among other things, on the identification and testing of firearms and weapons.

Given the amount of smoke generated during its frequent use, the firing range’s ventilation system was designed with a much higher-than-average air exchange rate to ensure smoke from the firearms is removed from the space quickly. Special ventilation keeps the space under negative pressure so smoke generated also doesn’t migrate to other spaces in the building as well.

The walls, floor, and ceiling are specially designed to withstand shots fired in the shooting range. A water tank for testing pistols is also located within the unit, which is also responsible for microscopic comparisons of projectiles and cartridge casings, gunshot residue patterns on clothing, and serial number restorations.

Forensic lab design is also impacted by the nature and condition of the evidence it is designed to test and analyze. Namely, some evidence entering the lab is wet, bloody, or just plain smells bad. An evidence drying area was designed into the building’s third floor – near the evidence receipt area – where special lockers are used to dry bloody or wet clothing. The ventilation system is also designed to help prevent odors from migrating into other spaces.

Getting the Biggest Bang for its Forensic Buck
The SLPD’s new forensics laboratory, of course, contains much more than firearms, DNA, biology, and chemistry units. A Trace and Arson Evidence Unit on the building’s second floor investigates accidents and cases involving arson residue, paint, and glass. Microscopes are used to analyze fibers, hair, fabrics, and shoeprints. The department’s ten scientists and its chief criminalist are each provided with administrative cubicles on the buiding’s second floor as well.

In addition to the evidence receipt area and firearms unit, the third floor houses a fingerprint area and photo lab, as well as computer-aided-design graphic facilities for creating crime scene drawings, maps and diagrams for trial. The third floor, which provides direct access to the adjacent police headquarters building, also includes administrative space and the ETU Workroom that evidence technicians call home when they are not out on the street gathering evidience.

The size and adjacencies of these various spaces were all carefully planned to help ensure the SLPD got the biggest bang for its forensics buck.

While the city-run lab is clearly the SLPD’s first choice for forensic testing and analysis, it has another option. If it chooses, it can send evidence to a state-run forensics lab in Jefferson City, MO., whose services are available to the department at no cost. Recognizing this “back up” service was available when the need arose, the SLPD lab planners chose to place greater priority on their lab’s drug analysis, DNA testing, firearms testing, and fingerprint analysis areas — areas that could provide police with positive identification of a suspect. These were also areas where the department would most benefit from priority service and fast turnaround – things they could not depend on from the state-run lab, the only other accredited forensic lab in the state.

A ‘Future-Proofed’ Design
The forensics scientists of the 1930s could not have predicted the sea change that DNA testing, automated evidence tracking systems, and other technological advances would create in their laboratories. And there are, no doubt, new methods and technologies ahead that today’s scientists can still barely imagine. Still, the SLPD’s new Forensics Lab is as prepared for the future as it can be for anything. The DNA Unit, for example, was designed with the future in mind. Should the SLPD choose to pursue robotics, for example, space is available to automate some sample-handling tasks, enabling more samples to be tested in less time. The cubicles in administrative area of the DNA unit were designed extra-wide to accommodate additional staff as the need arises.

The forensics building itself has been wired with fiber optics to the conference room, firearms examination room, and DNA areas, in anticipation of technologies that demand ever increasing bandwidth. Even the photo lab’s design acknowledges the paradigm shift that continues to occur in photography. Two photographers run the lab, which is responsible for photographing evidence in their photo studio, developing crime scene film, and preparing presentations for court, among other things. These photographers today operate a film-based lab that prints photos digitally or saves them to a CD. They recognize that the future of photography is digital. But they also recognize that the SLPD’s investigative officers are currently equipped with 35 mm cameras. So they are prepared to make the transition, one step at a time, and have the film processors and scanners that can adapt along the way.

And such is the world of crime-fighting. You make the best possible use of the latest tools and information currently available, while being open to and prepared for “whatever comes next.” The SLPD’s new $8.5 million Forensics Lab delivers all that – and makes solving crimes safer and more secure in the process.

Ken Francis serves as architectural department manager and senior project manager for the St. Louis office of Burns & McDonnell Engineers. He can be contacted at kfranc@burnsmcd.com or 314-821-9016.

Harold R. Messler is manager of criminalistics for the St. Louis Metropolitan Police Department. He holds a bachelor’s degree in chemistry from the University of Missouri at St. Louis. He can be contacted at hrmessler@slmpd.org or 314-444-5543.