Real world crime-solving is not like CSI
Collecting, analyzing evidence is time-consuming but worth the effort
By Susan Hoffman
Charlotte (FL) Sun-Herald
October 16, 2006
NORTH PORT -- Every Thursday evening, Gil Grissom of "CSI" solves another murder case on TV. He and his team examine the crime scene, collect all the right fibers and body fluids, process the evidence and come up with the answer, all within the space of an hour (with time out for commercials).
So why hasn't North Port made an arrest yet in the Coralrose Fullwood
homicide case?
It's never that easy in real life.
"We call it the 'CSI Effect,'" said John King, Florida Department of Law Enforcement Special Agent supervisor. "We see it often in trials: People in juries try to compare a real case with what they see on TV, and find (the real case) is not as exciting."
King and his colleague, Special Agent Vince Dellacchio, explained that people often have unrealistic expectations that DNA, fibers, fingerprints and other evidence can be recovered at every crime scene. But that's not always possible, Dellacchio said.
Criminalistics Specialist Pam Schmidt of the North Port Police Department said she often has to explain, "This is not CSI." Schmidt is responsible for collecting evidence at most crime scenes in the city. She said it is a tedious, painstaking process.
First, material has to be found and collected. She will often use an "alternate light source" like ultraviolet light to discover the presence of body fluids at a scene. Trace evidence such as hairs and fibers must be gathered. Each separate item is packaged, labeled, sealed and properly stored, depending on the type of evidence it is.
For instance, liquid body fluids must be refrigerated. The department has special lockable refrigerators for that purpose.
"Ultimately, (our work is) geared to getting a successful prosecution. We don't want defendants to find loopholes," Dellacchio said.
King added, "We have a duty to the victims to do a quality investigation. We also do not want to make false accusations against an innocent person."
Painstaking process
Schmidt, who has been in law enforcement since 1988, has been North
Port's chief evidence specialist since 2003. She's had 250 hours
of specialized training. "There is so much to this job that
people never see: the paperwork, the time on the computer, and all
the time you're being pulled in all directions."
Evidence must be sealed and labeled to maintain the chain of custody. Anyone who opens the evidence package must reseal it, and the evidence must be accounted for at every step.
When Schmidt has collected and packaged evidence from a crime scene, it generally goes either to the Sarasota County Sheriff's lab or to an FDLE lab in Tampa or Fort Myers. She may deliver it in person or send it via an express package service.
Nancy Ludwigsen, a forensic scientist with the Sheriff's Office, processes evidence for North Port. "About 80 percent of what we do is drug testing," she said. Her lab may process body fluids or suspected drug samples. Fingerprints are also analyzed here.
Schmidt said Sarasota County accesses AFIS, the Automated Fingerprint Identification System. The database covers the state of Florida and includes fingerprints of convicted criminals.
"People who have not been convicted of a crime generally are not in the AFIS database," Schmidt explained. She said parents whose children are printed for safety or job applicants who are fingerprinted need not worry that those prints are kept. "There's a right to privacy," she explained, that prevents those prints from being added.
Schmidt said there are certain features of a fingerprint that make it distinctive: certain ridges, bifurcations and the like that are important in fingerprint identification. These are termed points of minutiae and, to be usable, a print must have at least eight to 12 such points.
The prints are submitted to the Sheriff's lab and a computer program actually runs the comparisons of the sample print against a database of thousands covering the entire state. It may take more than a month for the print to be tested, due to backlogs, but only minutes to find any matches.
Sometimes law enforcement may get a "reverse hit," Schmidt explained. An unknown print found at a crime scene can be submitted but no match is found. Those unknown prints are kept in the system. Later someone may be arrested for an entirely different crime, and when the prints are run through AFIS, it is matched with the unknown sample. Hence, Schmidt said, a criminal may be identified many years after the crime was committed.
Results from any testing are returned not to Schmidt but to the lead detective assigned to the case. The detective, perhaps in consultation with the prosecuting attorney, may use those results to determine whether an arrest is justified, whether a search warrant is needed, or whether someone can be excluded as a suspect.
Karen Cooper, a crime lab analyst supervisor for FDLE in Fort Myers, said the time it takes to process a sample depends in part on how much of a backlog there is. She said it can take several months before a fingerprint or a drug sample can be analyzed.
"If there are high priority cases that come in, they may take precedence. Other things just have to wait a bit longer," Cooper said.
Schmidt described her job as a "humbling experience." She said, "Sometimes I see things no person should ever have to see." But she has also had the satisfaction of knowing that evidence she has collected is all they have to solve the case.
The miracle of DNA
DNA -- deoxyribonucleic acid -- is the foundation of the genes in all
living organisms. DNA is unique for every individual (other than
identical twins). Like fingerprints, DNA testing can be used to identify
an individual and is extremely reliable.
Ludwigsen said DNA evidence is usually sent to the FDLE lab in Tampa. "CSI shows these tests being done in minutes, but in reality it takes a minimum of two weeks, and that's assuming no backlog." She also said DNA samples may be hard to collect and can be easily contaminated.
King said DNA testing is done using the Short Tandem Repeat (STR) method. This is a laboratory process that amplifies and replicates the DNA material for evaluation. The worse the sample, the more it must be amplified and the longer it takes. The advantage in this method is that extremely minute samples that could not be tested previously now can yield usable data.
Ludwigsen noted one case in which the only evidence was a single hair -- previously not enough to run DNA analysis, but now able to be tested with the STR process. The resulting DNA profile was enough to help obtain a murder conviction.
Ludwigsen said cold cases have been re-evaluated using these new techniques years after the crime was committed. Ludwigsen mentioned the case of Elbert Walker who for decades was considered the most probable suspect in the 1959 murder of an Osprey family. DNA analysis of evidence collected at the scene did not match Walker's, and he could thus be excluded as a suspect.
The DNA profile is compared with CODIS, the federal Combined DNA Index System. CODIS includes data collected from convicted criminals (offender index) as well as unknown samples from crime scenes (forensic index) from all over the United States.
King said originally only people convicted of sex offenses were included in the Florida DNA database. Later, violent crimes such as homicide and assault were added. Recently, Florida law expanded to include DNA data for anyone convicted of a felony.
Ludwigsen said DNA tests start at around $1,500 each but can be more expensive if special processes are required.
Sarasota County was one of the first jurisdictions to get a "hit" on the interstate DNA database, leading to a conviction. DNA collected from a rape victim matched Mark Daigle, whose DNA was in Virginia's database from a burglary conviction years before. Daigle was ultimately convicted of the rape.
Ludwigsen explained that DNA analysis in the United States now relies on 13 key loci, or points, that are highly variable among all human beings. If you get a match on those 13 loci, the likelihood of a mistake is on the order of 1 in a quintillion (1 with 18 zeros after it).
Even more advances are being made in DNA analysis. A technique to evaluate "mitochondrial DNA" can be used to predict such features as race. A Sarasota company called DNAPrint Genomics can provide information indicating the likely ancestry of an individual: Sub-Saharan African, Native American, East Asian or European. Recently this testing was used in the case of a Louisiana serial killer to redirect the investigation and ultimately arrest and convict a suspect first omitted as a suspect.
Intense training and certification
Schmidt has been North Port's crime scene expert for only a few years, but already she has logged around 250 hours of extra training. She's had classes on everything from how to collect trace evidence to digital photography. She also must keep up with changes in the law.
Ludwigsen is trained in six disciplines and is currently working toward a master's in molecular biology.
Programs like "CSI" have attracted a new crop of prospective forensic specialists, and many turn locally to Edison College for forensics training. Dennis Fahey, criminal justice professor, said the school has its own crime lab and an apartment where crime scenes can be staged for learning.
"Once or twice a year I also set up a 'crime scene' somewhere else on campus, to give the students hands-on training in collecting trace evidence and getting fingerprints." Students learn how to collect and process evidence.
"They also learn that this job requires long hours, and it's not for everyone," said Fahey. "I make sure they know that, unlike on TV, they aren't going to be driving Hummers or wearing $1,000 Armani suits to work."
The program began six years ago and several graduates are now working in law enforcement. "One of our graduates is in the Marine Honor Guard assigned to the President," Fahey said.
In addition to personnel training, good forensics requires the right equipment. Laboratories must be certified and accredited periodically. That means they must go through rigorous inspection and testing to ensure that their results are both accurate and reproducible. All testing and calibration must be carefully documented. Technicians must also undergo proficiency testing.
Cooper said the American Society of Crime Lab Directors performs periodic inspections and issues accreditation. This ensures that the evidence will be deemed valid and will stand up in court.
While many wish that evidence could be processed quickly and suspects arrested before the next commercial break, the reality is that collecting and analyzing crime scene evidence is a time-consuming, painstaking process. The tests can be expensive and take a long time to complete, but as John King said, "We only have one chance to get it right. The time we invest in a case is geared to assure a successful prosecution."
You can e-mail Susan Hoffman at shoffman@sun-herald.com.