Sneak thieves and cat burglars once covered their tracks by donning a pair of gloves — but no more. Their DNA can act as the smoking gun that leads to their capture, as one unsuspecting bank robber recently found out the hard way.
Police in Medford, Oregon, followed a suspect's mucous trail to make an arrest one year after he robbed the city's Rogue Federal Credit Union. After a teller mentioned the perpetrator sounded like he suffered from a head cold, investigators collected a used tissue at the scene they believed the suspect had left behind. Forensic analysts later developed a DNA profile from the tissue that matched a record in the state's DNA database.
Once relegated to major crime scenes, where investigators gathered biological evidence from blood, semen and hairs, authorities are now unearthing the utility of applying CSI-style, DNA analysis techniques to high-volume serial crimes, such as burglaries, robberies and acts of vandalism.
"Fingerprints, shoe prints and tool marks have long been the bread and butter of burglary crimes — that's what everyone looks for," says Dean Gialamas, the director of Forensic Science Services for the Orange County (California) Sheriff's Department, which processes approximately 35,000 cases per year. "We're now extending investigations one more notch to include DNA, saying this is another piece of forensic science that could answer a lot of questions in lesser crimes."
Orange County's efforts have paid off. The department, which began collecting DNA in select robbery, auto theft, burglary, larceny, gun possession and drug possession cases more than 4 1/2 years ago, has processed approximately 400 burglary cases. In this internal evaluation, the agency received 60 cold hits in the database from those samples. "That's pretty phenomenal percentage-wise," says Gialamas, who serves on the NIJ's working group on DNA forensics. "We quickly saw the value of pursuing this more aggressively."
DNA does pay
In 2003, the Miami-Dade Police Department received two NIJ grants allowing it to outsource DNA profiling for high-volume serial crimes. While Miami-Dade officials expected some profiles to match those in Florida's DNA database as a part of this effort, Bud Stuver, laboratory manager of the forensic biology section of the Miami-Dade Crime Lab, says he and his colleagues never anticipated that of the 2,700 samples processed the match rate would be as high as 52 percent.
"When I look at it in hindsight, it makes perfect sense," he says. "The individuals who perpetrate burglaries, break-ins and steal automobiles are very recidivistic people. Many of them have a history of drug use or some other type of habit. Committing these crimes allows them to support the lifestyle they have."
Stuver clarifies the matches they obtained didn't necessarily "solve" a crime, however. The agency had two types of hits coming in. In the first category, the sample matched the DNA profile of a specific individual, whereas in the second, the submitted profile matched DNA found at another crime scene. "In this case, we've identified the same perpetrator likely committed various burglaries," he says. "So you have the potential for a serial offender."
Through Orange County's DNA collection efforts, whether for a major or minor crime, Gialamas says they've found that whenever there is a hit, there's nearly always a high-volume lower felony crime on the individual's record. "The criminal propensity for accelerating and graduating to more serious crimes is the reason why I think if we take DNA at a much earlier standpoint and increase the size of the DNA database with convicted felons and crime scene samples, the odds of making a connection will rise substantially," he says.
That's not surprising either, says Stuver, who uses the word "opportunistic" to describe individuals who commit lesser crimes. These offenders take advantage of whatever situation arises, explains the 38-year veteran of forensic science. If their intent is burglary and they enter a home and find a female alone, it may become a sexual assault. If they encounter resistance from victims, the situation may escalate to homicide.
Cost effectiveness, however, is not as easily judged — it all depends on an individual's perspective. An average DNA case runs up an approximately $2,000+ tab in forensic science, analytical time and supplies. Is spending $2,000+ worthwhile to solve a $400 crime? Economically the answer appears to be no.
But consider the United Kingdom, where the National DNA Database (NDNAD) houses profiles from individuals arrested for, or suspected of, involvement in any crime, from minor to major criminal acts. "The U.K. has found crimes can be prevented by processing DNA on lesser crimes," Gialamas says. "U.K. statistics site that for every DNA conviction obtained, you are preventing up to eight future crimes.
"If the U.K.'s statistics are accurate, and you can prevent crimes by solving one crime, then the $400 burglary, which cost us $2,000 to solve, is priceless," Gialamas continues. "What price would you put on being able to prevent a family member from being raped or killed? If that cost is spending a few extra dollars on a burglary case, I'm sure everyone would agree it is money well spent."
Touch or trace DNA
The secret to the success of using DNA as evidence in lesser crimes hinges on altering the way law enforcement views DNA, says Robyn Lacks, Ph.D., assistant professor at Virginia Commonwealth University's L. Douglas Wilder School of Government and Public Affairs.
"In the past we've always thought about the things we visibly see," she says. "We forget about sweat or saliva — things that might not be visible to the naked eye."
For DNA evidence to be effectively collected in these cases, investigators must be cognizant of where DNA might be discovered, emphasizes Gialamas. Specifically, officers must know what constitutes touch or trace DNA, he adds.
Trace DNA is when fingerprints or other small amounts of DNA are present. "When we have non-blood, non-semen DNA, this is what's thought of as trace DNA," Lacks explains. "Touch DNA, on the other hand, is found where the individual might have touched — assuming he or she didn't have gloves on — where they would have left sweat behind."
Touch or trace DNA isn't harder to collect than the other, but it is overlooked more easily, Lacks admits. "A pool of blood stands out to you. If someone is raped in the bedroom of her home, you know where to look for semen," she explains. "But you're going to have to think about where DNA could potentially be located in a property crime, and remember that most of it will be invisible to the naked eye."
Good investigation practices help pinpoint DNA at the crime scene. The Orange County investigative team contacts victims to learn which items the suspect may have tampered with, specifically objects the residents do not routinely touch or move, says Gialamas. A good example might be an area of a room the occupants don't normally enter, where things have been moved or disturbed. Investigators also search for items the perpetrator left behind — for instance, cigarette butts in a home of nonsmokers or an empty beer can the homeowners say is not theirs. "These are areas we are keying in on because of the high success of being able to recover DNA," Gialamas says. "We're finding touched items, handled items, drink containers, clothing left behind — all may have lingering traces of the perpetrator's DNA."
Gialamas points out the Orange County forensics lab has successfully retrieved DNA from many types of evidence. In a recent bank robbery series, the perpetrators cut eye holes in ski masks so they could see and left the cutouts behind, he says, "and that was enough for DNA samples.
"These are the kinds of things investigators would normally look at and ask, 'What could you possibly get forensically from this?' " he adds. "It's fiber, so maybe you could get something — but fibers don't tell you much. But, it turns out simply handling the objects may yield DNA."
His organization trains investigators to hone in on areas where the perpetrator got a little sloppy. For instance, the suspect may enter the scene gloved up to protect himself from detection but later remove them to access jewelry boxes and other small cases. One of Orange County's earliest hits matched a convicted felon in the state DNA database. Though felt is not amenable to producing fingerprints, the agency learned it is possible to retrieve DNA from it after collecting this offender's DNA off the felt lining of a jewelry box. That individual has since pled guilty for the crime and sits behind bars — something that may not have been possible if investigators overlooked felt as a possible contributor of DNA.
Stuver agrees investigators must broaden their thinking about DNA. "It's a hearty, robust molecule that sticks around for a long time," he says. A short time ago when Miami-Dade officials were investigating a homicide where an offender strangled a woman in a parking lot, the only clear evidence they had was a weathered piece of rope. Lab analysts found substantial amounts of DNA where the subject had grabbed the ends of the rope to pull it tight around the victim's neck. "We got so much DNA off of it," he recalls. "Our first thoughts were 'We'll give it a try, but we don't have great expectations.' But it proved us entirely wrong and it's just one example of many. You might think something that's been out in the weather or a rough surface may not be condusive to trapping DNA, but with DNA you can't make these blanket assumptions. You have to try and test as many things as you possibly can."
Navigating backlogs
Nearly every forensic lab in the county has a backlog for processing evidence. Adding DNA profiles for lesser crimes could bring these backlogged DNA processing centers to the brink of disaster. To navigate this storm, it's critical for agencies to limit the types and numbers of samples collected at property crimes, notes Gialamas.
"You don't want to go into a crime scene and collect 30 to 40 samples to process," he explains. "That would be a waste of time and effort. You need to hone in on where you get the best value."
Though Orange County employs more than 150 technical and support staff working in the crime lab, these individuals serve more than 100 local, state and federal agencies in the county. Yet, through good case management, where the lab limits samples from high-volume serial crimes to four, the department maintains its backlog rate at less than half the national average. Where most DNA laboratories experience a turnaround time of six to nine months, the Orange County lab offers an average 60-day turnaround time, with samples from major crimes usually being returned within 30 days.
Developing such a case management program, where crime lab officials review submitted evidence then determine which evidence provides the most probative value, helps reduce the number of samples processed, adds Stuver, who notes one of his job duties is to review submitted evidence for its probative significance. The case manager, when faced with a burglary scene, for instance, might find that blood where the subject appears to have cut himself will yield better results than DNA from a frequently accessed bureau drawer. Likewise, an item the offender left behind, such as a crowbar, has more probative value than a swab taken from a doorknob because it's possible to attribute the object's origin back to the offender. "A cigarette in a home where people don't smoke, clothing the subject left in the home or maybe a vessel the offender appeared to have drank from and left it on the counter — that's good evidence," he says.
What isn't great evidence, according to Stuver, is samples coming from surfaces touched by multiple individuals. Doorknobs, bureau drawers, etc., may yield DNA, but to be effective, the investigative agency must obtain elimination standards from every person who might have come in contact with the surface. "The DNA analyzed would be a composite of the various contributors' who would have come in contact with that surface," Stuver explains, noting a complex sample makes it hard for investigators to differentiate between the various contributors. "If it's a too well handled surface, you won't be able to get anywhere with it," Stuver emphasizes.
Another consideration must be whether to dust an area for fingerprints or collect DNA. The same sites being scanned for fingerprints are places DNA may be present, Lacks explains. But if investigators dust for fingerprints, it contaminates any DNA present. Thus, officials must decide between lifting a fingerprint and running it through AFIS versus collecting DNA and submitting it to CODIS. "When it comes to identification techniques, identifying individuals through fingerprints is hands down the best way to do it," Gialamas says. "When looking for DNA we may seek areas where fingerprints do not exist or where they are just smudges."
Some excellent sources of DNA arise where there's a partial print or a surface from which a quality fingerprint cannot be lifted. Take for instance a concrete wall; the grooves in the concrete make it difficult if not impossible to dust or lift a print from it. In this case, DNA is the better option. "It has to do with the surface the print is on, the quality of the print and then considering whether you will have a better chance of getting a hit through AFIS, which can be done back at the department, or through DNA, where you might have to wait two months for it to be processed," states Lacks.
Keep it clean
Touch or trace DNA, being invisible to the naked eye, is also easily contaminated. Anyone who enters and leaves the crime scene will leave DNA behind, according to the basic laws of transference spelled out in Locard's exchange principle. "For this reason, good crime scene investigators show up armed with gloves, booties, masks and so forth to reduce the possibility of contamination," Lacks says. "This is critical with touch or trace DNA because you cannot see it. You might destroy it because you don't know it's there."
Those at the scene must ward against contamination as much as they possibly can.
Take for instance an Orange County crime scene where a DNA sample matched a profile from a different crime scene — a case-to-case hit. Officials originally suspected the same individual committed these crimes. However, the investigative process revealed a detective at the scene of both crimes had inadvertently left his DNA behind.
"Officers and deputies must recognize their actions could cause them to leave their own DNA, and take the appropriate precautions," Gialamas says, noting it's crucial that agencies establish a database of elimination samples, or standards, from those who regularly process crime scenes.
Because talking spreads an individual's DNA across an area, Orange County requires officials to converse outside of evidence collection sites. Besides donning protective gear, responding officers in this agency also are instructed to secure the location, cordon the area off and then determine a path through the scene that reduces the possibility of evidence contamination.
Finding the right guy
"We've been extremely successful in retrieving DNA — we're able to recover DNA in 68 percent of our burglary cases," says Gialamas. "That's pretty phenomenal because it means in most cases we come across, we're going to find DNA."
The advantage is DNA is prevalent at the crime scene. The disadvantage, however, is it may not be the offender's. "There's no doubt in my mind you're going to find DNA at any crime scene — locating DNA is not the issue," Gialamas emphasizes. "It's finding the DNA pointing to the perpetrator that is the problem."
"DNA is not the end all to be all," he cautions.
Finding "foreign" DNA at the crime scene, does not necessarily mean it's from the perpetrator. In one cold hit involving a burglary at an Orange County residence, the point of entry was a broken window. By the time crime scene investigators arrived to process the scene, the homeowner had replaced the broken glass. "On the windowsill was a tiny drop of blood, which we expected to be the suspect's," Gialamas says. "We had every reason to believe this was the case, given the crime."
Forensic analysts ran elimination samples on household residents and from the investigative agency, eliminating anyone who had legitimate contact with the residence. They then submitted the profile to the state database and got a cold hit. Investigators contacted the suspect and learned he was the contractor who'd installed the new window.
"This is a good example of forensic science doing exactly what it is expected to do," Gialamas says. "We found a sample, got a DNA profile, received a hit, but it wasn't the complete answer. You had to rely on the total investigation. In this case, the window installer had a prior background, which is why he had a record in the system."
Gialamas warns everyone in the criminal justice community not to put DNA on a pedestal where they believe it will answer all their questions. "In any criminal investigative process," he says, "it is the totality of the investigation — the quality of the work of the investigator, the crime scene responder, the crime lab personnel — that leads to any success."
