DNA—the common abbreviation for deoxyribonucleic acid—is the genetic substance that determines the characteristics of all living things. DNA consists of two long, interlocking molecular chains. The links of these chains are called bases and a portion of these bases is unique to each human being. Only identical twins share the exact same sequence of DNA bases. Consequently, DNA bases hold the key to distinguishing biologically between one human being and another.
At crime scenes, DNA samples can be collected from blood, hair, skin, saliva, and/or semen. These samples can then be compared to the DNA profiles of suspects in the case. In addition, as a result of the federal government establishing an index system called CODIS (Combined DNA Index System), samples of DNA gathered at crime scenes can be compared to DNA profiles stored in state data banks. In the United States, all fifty states have enacted laws to provide for the collection and retention of DNA samples of all individuals convicted of murder and/or sex offenses. Forty-seven states require all violent offenders to submit DNA samples and thirty states actually require ‘‘all felons’’ to provide DNA samples to be stored in CODIS. Currently, CODIS contains information from over six hundred fifty thousand convicts.
Although CODIS was instituted in 1994, DNA evidence has been extremely useful in helping to identify, apprehend, and convict some of the most violent criminals in sexual assault and homicide cases since the mid-1980s. When properly collected, tested, and preserved, DNA provides an accurate means of identifying and eventually convicting individuals who left DNA at the scene of a crime.
However, DNA can also be and has been a viable tool for exonerating the innocent. Every year since 1989, the FBI has reported that, in 25 percent of the sexual assault cases that they handled, the primary suspects were excluded by forensic DNA testing. To date, there have been at least 150 cases in which DNA technology has been used to eliminate suspects who were charged with serious crimes that they did not commit or to exculpate individuals who were wrongfully convicted.
Approximately fifty nonprofit legal clinics in the United States now utilize DNA technology to help establish the innocence of their clients. Many of these clinics, referred to as ‘‘innocence projects,’’ are housed at universities where students of law, journalism, and/or forensics work together under the supervision of attorneys to establish evidence that will exonerate wrongfully convicted individuals.
These innocence projects make use of state statutes that allow defendants to access DNA testing in order to prove their innocence. Thirty-eight states have now enacted postconviction state statutes related to DNA testing. Most state statutes, however, are limited in scope. For example, in many jurisdictions, DNA testing is limited to defendants who have claimed innocence at trial. Consequently, defendants who plead guilty in state courts are prohibited from accessing DNA testing. Thirty-three states also deny access to DNA testing if the defendant fails to request testing within six months of being found guilty.
Like state prisoners, federal prisoners are also allowed access to DNA testing if they assert their innocence. Under the Innocence Protection Act (which took effect on October 30, 2004), a federal criminal defendant may obtain DNA testing by filing a motion on or before October 2009 or within three years of being convicted.
In addition to establishing rules and procedures to govern DNA testing of federal prisoners, the Innocence Protection Act also provides funding to state governments to review systematically all death penalty cases in which DNA testing may be appropriate. The law does not, however, compel states to develop postconviction DNA testing and procedures equal to the federal guidelines. Consequently, many state criminal defendants can and will be denied access to DNA testing.
One of the simplest ways in which defendants are denied access to DNA testing is when prosecutors and state officials, under political pressure to reduce crime, destroy physical evidence as soon as the appeals process is exhausted. In destroying the evidence, these officials destroy the possibility of a defendant’s access to DNA testing. More stringent state laws governing the retention of physical evidence in criminal cases could help resolve this problem and thereby guarantee greater access to justice for the wrongfully accused and convicted. Technology is always advancing, so often physical evidence can be subjected to new DNA tests that had not previously existed. This new technology could be the key to freedom for some individuals. But without the physical evidence to test, no such hope of freedom exists.
In the event that exculpatory DNA evidence is obtained, a new trial will generally be granted. In some instances, however, exculpatory DNA has not resulted in the granting of a new trial. For example, when Joseph O’Dell presented a Virginia court with exculpatory DNA evidence, the court indicated that the evidence did not matter and O’Dell was subsequently executed. Unfortunately, courts in other jurisdictions have also concluded that newly discovered exculpatory DNA evidence does not necessarily mandate a new trial. Thus, although DNA testing has the potential to exonerate the innocent, it is not always procedurally embraced by the justice system.
In other instances, the potential of DNA to exonerate the innocent is mismanaged as a result of poor testing procedures. For example, the Pennsylvania State Crime Lab discovered that one of its scientists had performed shoddy DNA testing. They were consequently forced to schedule the retesting of 615 cases. The New Jersey State Crime Lab discovered that its scientists had failed to control for contamination of DNA samples and they subsequently reopened 102 cases for retesting. Similarly, the manager of the DNA Unit at the Oklahoma City Police Department Crime Lab was fired because of flawed analysis. It was disclosed that none of the scientists who worked in the DNA section of the Houston Police Department Crime Lab was qualified by education or training to do his or her job. As a result of this discovery, evidence in 378 cases had to be redone.
In 2005, another DNA scandal was brought in to public light. It was revealed that a Virginia State Crime Lab senior analyst responsible for conducting DNA tests in capital cases had made significant mistakes in DNA testing. As a result of this, 160 cases had to be re-examined. The mistakes committed by this analyst came to light after it was discovered that a DNA test that clearly supported the innocence claims of Earl Washington, Jr., a death row inmate, had been ignored. According to an audit report of the Virginia State Crime Lab, not only did the laboratory’s leading DNA analyst generate erroneous test results in a capital case, but also the laboratory’s system of retesting samples to catch these errors completely failed. The external audit of the Virginia State Crime Lab (allegedly the best DNA lab in the country) provided proof that crime labs should not be allowed to police themselves. Considering the professional relationship between crime labs and police departments, it is not surprising that a pro-prosecution bias sometimes exists and blinds individuals to the reality of exculpatory DNA evidence. If, however, DNA testing is to be used in the pursuit of justice, expert oversight of state police crime labs may be necessary to address this problem.
Despite the challenges that DNA testing presents, it is clear that DNA has the potential to provide reliable evidence of guilt as well as innocence. If the United States, as a society, is to realize this potential fully, management of and access to DNA testing must be improved and eventually perfected.
JUDITH A. M. SCULLY
References and Further Reading