Advances in Forensics Provide Creative Tools for Solving Crimes
[Note: This is an expanded version of the article that appears in the Bulletin of the Connecticut Academy of Science and Engineering, Vol. 19,2, Summer 2004.]
[Note: This is an expanded version of the article that appears in the Bulletin of the Connecticut Academy of Science and Engineering, Vol. 19,2, Summer 2004.]
Forensics -- the application of science to matters of law -- has made great strides in recent years, as advances in technology have given forensic scientists a variety of new tools.
Connecticut has made significant contributions to this progress. The state has gained visibility in the field of forensics through the work of the Connecticut State Police Forensic Science Laboratory and the Henry C. Lee Institute for Forensic Science at the University of New Haven.
Dr. Henry C. Lee, who established the laboratory at University of New Haven and later headed the state police forensic lab, is recognized around the world as a leading forensic scientist.
Given the state’s leadership in forensics and Dr. Lee’s prominence, it’s not surprising that plans for the proposed Connecticut Center for Science & Exploration include a crime workshop, called the Henry C. Lee Crime Laboratory, where youngsters can try to solve real cases.
When Dr. Lee speaks about forensic science, people listen. He has examined thousands of crime scenes and has lent his expertise to hundreds of high-profile criminal cases from the trial of O.J. Simpson to the re-examination of the assassination of President John F. Kennedy.
More recently, Dr. Lee and others from Connecticut — State Police Major Timothy Palmbach and former Chief State’s Attorney Austin J. McGuigan — were among the experts who went to Taipei to investigate the shooting of Taiwan President Chen Shui-bian.
Dr. Lee points to major advances in forensic science in a number of areas. DNA analysis is unlocking the mysteries of human identity. Image enhancement technologies are enabling investigators to read clues such as fingerprints, footprints and bite marks.
Data mining of databases, such the Combined DNA Index System (CODIS) and the Automated Fingerprint Identification Systems (AFIS) help crack cases that would have been unsolvable a few years ago. And computer science is enabling police to collect evidence from e-mail and other digital files.
Recent advances in forensic technology are built on centuries of progress in the field, Dr. Lee says. Forensics was born in the Middle Ages and matured with the growth of science and medicine in the 19th century. Capabilities expanded with the discovery of blood types and the wide use of fingerprints for personal identification.
The first police crime laboratory opened in Lyons, France, in 1910. Since then, police have been applying the scientific approach to crime solving with ever increasing sophistication.
Pioneer in Forensics
Dr. Lee has been in the forefront of these developments for many years. Born in China, he studied police science in Taiwan and served as a police captain there. He came to the United States in 1965 to study forensic science, and earned a degree from John Jay College of Criminal Justice and a PhD in human genetics and biochemistry from New York University. After working at the NYU Medical Center, he established a forensic science program at the University of New Haven in 1975.
Later he served as Director of the State Police Forensic Science Laboratory and Commissioner of the Department of Public Safety. Currently, he is Chief Emeritus for the Connecticut Division of Scientific Services and a professor at the University of New Haven.
Under Dr. Lee’s leadership, the University’s Institute of Forensic Science has encouraged a high level of scientific inquiry in the investigation of crimes. Courses and symposia teach advanced forensic techniques to professionals from the law enforcement, public safety and legal communities.
The Institute concentrates on promoting advanced and effective investigation of crime scenes. This emphasis focuses on evidence recognition, enhancement and documentation.
National Training Center
Building on its reputation for innovation, the Institute last year established a National Crime Scene Training Center. The facility is putting Connecticut on the crime-fighting map by teaching crime scene analysis to attendees from all over the country.
“In training professionals in the criminal justice field,” Dr. Lee says, “we recognized that it was difficult for them to get practical experience. Therefore, we began a program to accept cases from people who could not afford to hire a consultant. They pay us only for costs. These cases provide practical experience for our students while helping the community.”
Workshops also offer practical experience. For example, in a gunshot reconstruction course, investigators study bullet trajectory using an actual car that has been shot up. Another workshop teaches the difference between low-velocity and high-velocity blood splatter, and shows how to identify hits from a baseball bat and other instruments.
The Institute works to standardize the procedure for collecting and analyzing evidence from crime scenes. “There are many cases that were not solved because evidence at the scene was not properly recognized, preserved or collected,” Dr. Lee says. “In a notorious example, evidence was compromised when police covered Nicole Browne Simpson’s body with a blanket. Standardizing crime scene procedures can prevent this kind of problem.”
Research is ongoing into DNA analysis, biological evidence, arson and cyber crime. The organization is partnering with the National Institute of Justice to develop low-cost teleforensic capacity for law enforcement agencies; the goal is to use commercially available products to transmit high-quality images and data from a crime scene to a laboratory in real time for quick analysis.
Initiatives by State Police
In addition to the state police forensics laboratory in Meriden and toxicology lab in Hartford, a computer crime and electronic evidence center was established in 1999. Sgt. Joseph Sudol, commanding officer of the computer crime operation, says, “Today, police look for computer evidence in every type of crime, from homicide to fraud.”
Police mine narcotics dealers’ hard drives for records of their transactions, and they examine the e-mail correspondence of murder victims to uncover motives and identify suspects.
“In a homicide occurring 25 years ago, police would examine the victim’s address book and bank records,” Sgt. Sudol says. “Today, we get a warrant for the victim’s personal computer. We have software and hardware technology that enables us to look at the hard drive in a forensic way. We can recreate deleted files and recover instant messaging chats.
“Some 40 to 45 percent of our cases are related to child exploitation on the Internet,” Sgt. Sudol says. In a noteworthy case, two young girls were sexually assaulted in Hartford four years ago and the perpetrator videotaped the crime and broadcast it on the Internet.
The Navy spotted the tape at a military base in Japan and notified the National Center for Missing and Exploited Children. Using audio- and video-enhancement technology, the organization concluded that the crime occurred in Connecticut. Based on that small amount of information, the State Police identified the victims and the room where the assaults occurred — and arrested a suspect, who has been awaiting trial under a $2 million bond.
“New advances in forensic computing are occurring every day,” Sgt. Sudol says. “But it’s a constant struggle to keep up with new technology such as the miniaturization of cameras.”
When it comes to analyzing evidence, perhaps the greatest advance in forensic science was the introduction of forensic DNA analysis in 1985. Since then, millions of forensic DNA tests have been conducted in the United States and around the world. In a major advance, the analysis of DNA has evolved from a laborious process taking weeks or even months to a procedure that can be completed in a matter of two days.
“DNA proficiency has made revolutionary contributions to forensic science,” Dr. Lee says. “In the forensic world, its impact has been felt as profoundly as the discovery of fire and the invention of the Gutenberg press.
“Since this breakthrough in the 1980s, innovations and new applications have occurred with breathtaking speed. Advances in miniaturization and microchip technologies have been combined with the analytic techniques of DNA analysis to give us impressive new capabilities.
“DNA science has solved crimes considered otherwise unsolvable,” he says. “In addition, DNA has ended the careers of serial rapists and serial killers, identified the remains of soldiers missing in action, established paternity in many instances, helped medical detectives to track diseases, and illuminated countless other controversies involving biological issues.”
Police today commonly use DNA analysis and other technologies. They are less dependent on traditional crime-solving methods that have fallen into disfavor, such as interrogating suspects, talking with informers or relying on witness identification.
Swarm of Techniques
“Forensic DNA analysis is not a single technique,” Dr. Lee says. “It is a swarm of techniques based on the vast expanse of the human genome.”
Early techniques included Restriction Fragment Length Polymorphism (RFLP), human leococyte antigen analysis (HLA DQA1), and amplification fragment length polymorphism (AFLP). More recent developments include mitochondrial DNA (mtDNA), short tandem repeats (STRs), Y chromosome (YSTR) and single nucleotide polymorphisms.
Initially, DNA samples that were small or degraded were beyond the reach of DNA-typing techniques. Over time, however, new technologies have made it possible to test older and smaller samples. Now, a revolutionary process called polymerase chain reaction, or PCR, permits the faithful reproduction of small amounts of DNA.
PCR makes it possible to use the DNA from a coffee cup or even a single hair root to produce the larger volume of DNA needed to conduct a test. Even saliva found on the back of licked postage stamp can provide enough genetic material to conduct a sophisticated DNA test.
“With a small sample — even a decomposed or degraded sample — we can get an entire profile of an individual,” Dr. Lee says.
This was the case when the state police forensics laboratory sent twenty DNA scientists to assist in identifying victims of the 9/11 attack on the World Trade Center. Other examples include major fires and airliner crashes, where victims were burned beyond recognition or fragmentized, and mass killings in Bosnia and Cambodia, where traditional means didn’t exist for the identification of victims in mass graves.
“DNA also can be used to link cases together,” Dr. Lee says. “If we find the same semen DNA in different rape cases, we can conclude that we’re dealing with a serial rapist.”
Forensic scientists are combining advances in miniaturization and microchip technologies with well-established techniques of forensic DNA analysis. The fusion of these technologies could revolutionize DNA typing.
Until recently, DNA analysis had been used mostly in serious criminal cases such as murder, rape, terrorism or genocide. Since advances have streamlined DNA procedures and cut their cost, however, they are being used increasingly to investigate other offenses such as hit-and-run, burglary, robbery and white-collar crime.
DNA analysis will play a key role at the proposed Connecticut Center for Science & Exploration, the science center, scheduled to open late in 2007 in Adriaen’s Landing in downtown Hartford. According to current plans, visitors will be able to perform real DNA tests and try to crack murder mysteries. The Henry C. Lee Crime Laboratory is envisioned as a facility where 35 to 40 students can learn forensic science in a hands-on experience.
“The idea is to engage young people in the excitement of the scientific method so they’ll consider careers in science, math and technology,” says Dr. Theodore S. Sergi, president and CEO of the science center.
The use of DNA in crime investigation received a boost in 2003 with the expansion of the sex-offender DNA database in Connecticut. The legislature passed a bill last year to enlarge the database from sex offenders to all who commit a felony.
“This will help us solve more cold cases,” Dr. Lee says. Early this year the database helped identify a man who had killed a number of women in the Hartford area between 1997 and 2002. Based on evidence at the crime scenes, such as DNA on cigarette butts, police identified a suspect from the DNA database. Subsequently, the suspect was arrested, tried and convicted of the murders.
Advances also have been achieved in many other areas of forensic science, such as fingerprints. Technology also has improved in the ability to detect latent fingerprints, which are among the most valuable types of physical evidence in criminal investigations.
Fingerprints are accepted by the courts as good evidence for personal identification. There are many chemical and physical methods for detecting and visualizing latent prints at a crime scene. These techniques have expanded the capabilities of investigators at crime scenes.
Fingerprints can be systematically filed using classic fingerprint classification systems and automated identification systems. These files allow for the rapid retrieval of a particular fingerprint card and the arrest of a specific suspect.
When the 1975 homicide of a girl named Penny Serra went unsolved for 20 years, her father, John Serra, asked Dr. Lee to investigate. A review of the evidence uncovered a tissue box with bloody fingerprints. Chemical enhancement technologies made it possible to develop ridge characteristics. Searching the fingerprint database produced a suspect, who was tried and convicted.
Years ago, police depended on a brush to dust for fingerprints. Now they can use any of 250 different chemicals and instrumental techniques to enhance fingerprints. Police also use a variety of light sources and lasers. With these techniques, they can identify fingerprints that were difficult to recover several years ago.
Forensic laboratories can process physical evidence using various methods, depending on the nature of the latent prints. In addition to dusting with powder, techniques include using chemicals such as iodine, ninhydrin reagents, silver nitrate and fluorescent reagents as well as “super glue.” Many laboratories are also using advanced technology in instrumentation and illumination to enhance latent prints. These include argon laser, X-ray detection, vacuum coating and various light sources.
Advances in image-enhancement technology are helping police visualize evidence, such as imprints and impressions. Imprints are patterns left on hard surfaces. Impressions are three-dimensional patterns or indentations made in a softer medium such as mud, sand or snow.
A number of nondestructive photographic techniques have been developed to enhance imprints and impressions. These include the use of filters to vary contrast and alternate lighting techniques, such as oblique lighting, polarized light, ultraviolet light, infrared light and various wavelengths produced by alternate forensic light sources.
Images can also be enhanced with chemicals. The material picked up by a shoe to make an imprint could contain trace elements, minerals, blood and other compounds. These substances can be made more visible though enhancement using various chemicals.
Any kind of impression can be improved by image-enhancement technology — even bite marks. Digital imaging techniques can significantly improve the intensity and clarity of bite marks.
Video tape or photographs also can be scanned into a computer for image enhancement. In a case when a convenience store robbery was videotaped, Dr. Lee says, the poor quality of the image of the robber’s face initially made it impossible to make a positive identification. But color enhancement and other technologies clarified the image and led to identification of the robber.
“Whether it’s DNA, fingerprints, e-mail or other evidence, technology is giving us new tools that are helping not only to solve crimes, but also to prove the innocence of those wrongly accused,” Dr. Lee says. — Woody Exley
[Mr. Exley owns Exley Communications in West Hartford, CT.]