Sneak Thieves and Cat Burglars BEWARE

DNA evidence puts law enforcement hot on the perpetrator's trail in high-volume serial crimes.


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.

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