In 1987, Florida rapist Tommie Lee Andrews became the first person in the United States to be convicted as a result of DNA evidence. In 1989, Gary Dotson was the first person whose conviction was overturned using DNA evidence. In 1994, the “Crime of the Century” brought the power of DNA testing and impact of evidence contamination to the forefront of the public eye when Nichole Brown Simpson was murdered. These are only three of the massive number of cases heavily dependant on DNA analysis.

Over the past 20 years, DNA has become a critical part of our judical system. During this same period, the science of DNA processing has quickly changed; from scientific methods to instrumentation and caseload to staff. As the process evolves and technology advances, forensic laboratory facilities must also transform to support these trends and countless cases that rely upon DNA evidence.

The FBI’s Daisy Chain and New York City’s vertical separation by floor are perfect examples of evolving facilities. Various aspects of forensic laboratories are now being reevaluated to push the design envelope and provide even more flexibility. This article outlines how yesterday’s design affects today’s innovative laboratory trends. Each facility spotlighted utilizes modular planning concepts.


Facility Style – Daisy Chain. Planning for this facility began in 1996. It was occupied in 2002.

Design Intent – The Daisy Chain was designed for each scientist to move in one direction into and out of each lab without back tracking. For example, a staff member first would enter the gowning room, then move into reagent prep, next into Pre-Amplification, then Post-Amplification (AMP), and finally exit through the same gowning room.

Scientific Reasoning – The goal was to avoid cross-contamination by not back tracking from Post-AMP into Pre-AMP. In theory, once users have moved through the Daisy Chain, they are done for the day.

Staffing – The staff member responsible for completing each DNA analysis himself would manage the case material all the way through the process to completion. When this Daisy Chain layout was implemented, there were only a handful of scientists in this field. They were all at the Ph.D. level, and came from leading academic institutions to work in the forensic industry. Instrumentation – Early DNA facilities were associated with serology units and still utilized electrophoresis gels, RFLP, dark rooms, wet photographic techniques. They used early modelsof PCR equipment, centrifuges, and glove boxes.

The Science – Silver staining in the RFLP method provided visualization of very small amounts of biological materials, especially nucleic acids. This collection of fragments was then separated by length using electrophoresis, resulting in a particular pattern of fragment bands. In general, the bands are not visualized directly but are usually treated with a chemical probe so some of the bands may be clearly seen. Serology, the identification of bodily fluids, is now conducted in a completely different part of the building.

Caseload – Due to the judicial system’s unfamiliarity with the science at this time, requests for DNA analysis were not in high demand.

FORENSIC SCIENCE CENTER  Philadelphia, Pennsylvania

Facility Style – Horizontal. Planning for this facility began in 1999. It was occupied in 2003.

Design Intent – Developed from the Daisy Chain, horizontal flow facilities provide an even greater separation between Pre-and Post-Amplification activities because of the same concerns of cross-contamination. The staff and evidence move in one direction, from room to room avoiding back tracking.

Scientific Reasoning – A separate de-gowning exit area was added to this design that is not present in the Daisy Chain. Gowning and de-gowning areas are at separate ends of the facility. This adds another level of prevention to cross- contamination.

Staffing – Each staff member still has the responsibility of completing each DNA tasks himself throughout the case. The Ph.D. staff members now managed younger staff that has undergraduate and masters’ degrees in biology and biochemistry.

Instrumentation – The facility still used electrophoresis gels, dark rooms, wet photographic techniques, water baths, and silver nitrates. However, some of the equipment evolved to Biological Safety Cabinets and Dead Air Hoods in Pre Amplification. Automated photo processing equipment was used. Capillary Electrophoresis instruments were replaced with thermocyclers and genomic sequencers.

The Science – More sophisticated equipment was available to support the science. Large batches of samples could be tested in less time.

Caseload – The judicial system began to see the benefits of DNA evidence processing and requests for analysis started to increase. Questions regarding past cases also were beginning to emerge.



Facility Style – Separation of time and distance. Planning for this facility began in 1997. It is currently under construction.

Design Intent – Breaking the “Chain!” It is no longer necessary to move from one space directly into the next. It is possible to avoid cross-contamination while adding greater flexibility to access the labs at multiple points. Staff and evidence still move in one direction but staff members have the ability to enter or exit the process at any point.

Scientific Reasoning – The scientists start by gowning up in the Bio-Vestibule (BV) with a white lab coat. When scientists are ready to enter the Post Amplification area, they enter a second BV, remove the white lab coats and enter the Post AMP lab. Once inside they put on blue, or other distinct color, lab coat designated to wear only within the Post AMP Lab. When finished, they leave behind the blue coats, enter the BV and exit wearing white coats.

Staffing – The need for staff has tripled. In an effort to obtain the most experienced staff, “quality of life” has become a focus for each facility. The LA Regional Crime Lab incorporated several new features to enhance “quality of life” including specialized private rooms, dedicated office space, unit conference rooms, break areas, and large locker rooms.

Instrumentation – Old equipment was replaced with very sophisticated genomic sequencers and real-time PCR instruments. Biological Safety Cabinets and Fume Hoods are now supplemented by using local exhaust devices known as “snorkels.” Dark rooms have been replaced by digital imaging equipment. The Science – Serology has been tied into the DNA Unit; changing the name of the unit to Forensic Biology.

Caseload – There is a new term passed around the forensiccommunity known as the “CSI Effect.” Popular culture now directlyaffects the forensic lab. Persons in the judicial system are exposed to television programming that highlights the highly dramatized use of forensic science. DNA cases continue to increase with new grants to fund increases in staff and past cases are revisited to possibly pardon some convicted persons on death row.


Facility Style – Vertical. Planning for this facility began in 2000. It is currently under construction.

Design Intent – To vertically organize the DNA process in the facility and use dumb waiters to move evidence from floor to floor. The urban setting, expected 650 staff, and the focus of the Forensic Biology Unit strongly affected the Design Intent of this project. The scientists have access to each lab on every floor through Bio-Vestibules.

Scientific Reasoning – Separating the forensic biology activities, floor by floor, creates an additional barrier for the prevention of cross-contamination. This configuration increases flexibility for staff to access the analysis at multiple points. Staff and evidence still move in one direction, but with the ability to enter or exit the process at any point.

Staffing – The vision is that the staff will be cross trained in all aspects of Forensic Biology. In early stages of planning the facility, scientists expected heavy use of robotics in the facility would reduce the need for huge increases in staff. Now it is evident staffing will not be reduced but staff qualifications and work assignments will change. IT and maintenance staff capable of servicing the robotics systems will be needed for the facility to function properly.

Instrumentation – New equipment has been replaced with even more sophisticated robotic systems for processes from extraction to Post Amplification. Large decreases of large exhaust devices are enhanced by the use of snorkels. Additional equipment is used in training and conducting research in Forensic Biology.

The Science – Forensic Biology science continues to evolve and facilities and equipment advance to support the science.

Caseload – When DNA evidence was accepted by the court system, this opened an opportunity for law enforcement agencies and particularly crime scene investigators, to collect potentially valuable DNA evidence on a much wider range of criminal activity than crimes against persons. Terrorism cases are a very important use of DNA technology. Property crimes are a very large segment of crimes that now effectively use DNA technology. Even fingerprint technology, one of the first and most venerable of forensic sciences, can provide DNA for crime investigators.

As the science of DNA and Forensic Biology advanced over the last 20 years, the concerns of contamination and facility flexibility have become even more prevalent. As demonstrated in the four facility examples above, contamination must be considered with the utmost level of detail. Flexibility needs to be a focus in facility and laboratory design. With the high demands on DNA analysis within the courts, where would our judicial system be without reliable and accurate processing DNA evidence? How many criminals would be set free because of the suspicion of contamination?

Ken Mohr is a Principal and Sr. Forensic Laboratory Planner with Crime Lab Design, which provides full A/E services for forensic and medical examiner facilities.