On August 10, 1984, Deborah Sykes was raped, sodomized, and stabbed to death as she walked to work in Winston-Salem, NC. A month later, Darryl Hunt, then 19 years old, was arrested and eventually convicted for the crime. Hunt insisted that he was innocent and by 1990 improved DNA testing of semen found on Sykes proved that he was not its source. Nevertheless, North Carolina prosecutors ignored this new evidence and he remained in jail. Finally, further DNA testing eventually turned up a close but not perfect match to a genetic profile already in North Carolina's criminal DNA database. The police questioned the brother of the convict whose profile was in the database. That man, Willard Brown, then confessed to Sykes' murder in 2003 and Hunt was finally freed from prison.
In this case, DNA profiling exonerated an innocent man and helped lead the police to real culprit. It's outrageous that North Carolina law enforcement ignored earlier DNA profiling that excluded Hunt; however, the Sykes case illustrates how growing state criminal DNA databases can be used to help the police find criminals. Every state now collects and tests DNA samples from convicted felons and stores those profiles in computer databases. And five states—California, Florida, Texas, Virginia and Louisiana—go further, requiring not just felons but all people who are arrested for felonies to provide both fingerprints and DNA samples.
It is settled law that fingerprinting does not violate the Fifth Amendment's guarantee against compelled self-incrimination or the Fourth Amendment's prohibition of unreasonable searches and seizures. Indeed, much non-testimonial evidence does not fall under those constitutional protections, including the analysis of blood and breath for alcohol. Samples of semen, hair, and other tissues may be taken without a suspect's consent. Requiring arrestees to surrender DNA samples by swabbing their cheeks will likely be similarly found constitutional too.
"Cold hits" from DNA databases illustrate just how useful they can be in solving crimes. Basically, the police who have no suspect can run a DNA sample from the crime scene through their database and if it matches a profile that's already there, they'll know whom to go looking for.
On the other hand, civil libertarians properly object to a growing police tactic in which people who fit the description of a suspect are asked to "voluntarily" give a DNA sample as a way to exclude themselves from suspicion. Refusing to go along with these DNA dragnets naturally draws the attention of the police.
As the DNA databanks expand, their power to find criminals increases. For example, last week genetic researchers at Harvard University published a study in the journal Science explaining how DNA taken from a crime scene can be used to finger the kin of previously convicted felons. What happens is that the police may run a DNA crime sample through their database and find that it doesn't match someone perfectly. However, the sample may yield a profile very similar to one that is already on file. This suggests that the perpetrator who left the DNA behind is a brother, father, sister, or mother of someone whose DNA profile is already in the database. This gives the police the clue that they should be looking for a close relative of a convict as a suspect. As the Sykes murder show, the technique works.
Kinship DNA searching is thought to be different from using fingerprints because fingerprinting can generally incriminate only one person (though similar fingerprint patterns can sometimes point to a relative as a criminal perpetrator). DNA kinship searching necessarily implicates both guilty and innocent blood relatives of the person whose profile is in the databases. As Harvard researchers Frederick R. Bieber and David Lazer note, "Genetic surveillance would thus shift from the individual to the family."
DNA kinship searching will not solve every crime because in order for it to work, the DNA profile of a close relative must already be on file. Interestingly, it turns out that according to a 1999 Bureau of Justice survey, 46 percent of prison inmates had at least one sibling, parent or child who had been incarcerated at some point. This sad fact increases the chances that DNA kinship searching will turn up a suspect. Of course, if you happen to be the good kid in a family of crooks you will be understandably annoyed by a police "request" for your DNA, but, on the other hand, it would be silly for the cops to ignore clues from kinship DNA searches.
One suggestion for avoiding DNA kinship searches which casts suspicion on guilty and innocent family members alike would simply be to require that every American have his or her DNA profile in a database. The idea is that law enforcement officials could simply check whatever DNA samples they obtain from a crime scene with the directory for a perfect match. The FBI already has a computerized database of 250 million sets of fingerprints representing 74 million people. I predict that since collecting DNA is no more invasive than fingerprinting, it seems very likely that a similarly sized national DNA database will be created in the near future. And who knows—someday your genetic profile may be embedded in your national ID card too. Heck, who needs a national ID card if every cop has a fast DNA reader and wireless electronic link to the comprehensive national DNA database? If we want to avoid becoming a database nation, the time to stop it is now.