DNA Evidence in Criminal Justice: Convictions and Exonerations
This paper examines the role of DNA technology in the United States criminal justice system, focusing on both its power to convict the guilty and exonerate the wrongfully imprisoned. Drawing on peer-reviewed sources, congressional records, and documented case studies, the paper surveys post-conviction DNA legislation across U.S. states, reviews exoneration statistics from 1989 to 2003, and analyzes specific cases involving serial murder in Los Angeles and wrongful rape convictions in Illinois. It also addresses the privacy concerns raised by familial DNA investigations and calls for expanded DNA testing infrastructure nationwide.
- Introduction: DNA Technology and Criminal Justice: DNA's revolutionary role in U.S. criminal justice
- Post-Conviction DNA Testing and Exoneration Statistics: State legislation and federal DNA testing acts
- Exonerations in the U.S.: 1989 Through 2003: 340 exonerations and prosecutor resistance
- Familial DNA and the Capture of a Serial Killer in Los Angeles: Familial DNA used to identify serial killer Franklin
- Wrongfully Convicted Rapists Exonerated by DNA Testing in Illinois: Bullock, Cruz, and Hernandez freed by DNA evidence
- Conclusion: The Case for Expanding DNA Testing: Policy call to expand DNA testing infrastructure
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What makes this paper effective
- The paper grounds abstract policy arguments in concrete, named case studies, making statistical claims tangible and emotionally resonant for readers.
- It balances two sides of DNA's impact — both convicting the guilty (the Franklin serial murder case) and freeing the innocent (Bullock, Cruz, Hernandez, Jones) — giving the argument appropriate scope.
- Direct quotations from prosecutors who resisted acknowledging wrongful convictions add rhetorical force and illustrate systemic resistance to reform.
Key academic technique demonstrated
The paper effectively uses case study evidence to support a policy argument. Rather than relying solely on statistics, the writer selects representative individual cases that illustrate broader patterns — such as racial disparity in wrongful convictions and prosecutorial misconduct — while still anchoring claims in peer-reviewed sources like the Columbia Law Review and Journal of Criminal Law & Criminology.
Structure breakdown
The paper opens with a congressional quotation to establish policy urgency, then moves through a legislative overview, national exoneration statistics, a high-profile conviction case, and two detailed Illinois exoneration cases before closing with a normative policy recommendation. This funnel structure — from macro statistics to micro case studies to a concluding call to action — is well suited to criminal justice research papers at the undergraduate level.
Introduction: DNA Technology and Criminal Justice
"Unfortunately, the current Federal and State DNA collection and analysis system suffers from a variety of problems. In many cases public crime laboratories are overwhelmed by backlogs of unanalyzed DNA samples, samples that could be used to solve violent crimes if the States had the funds to eliminate this backlog…" (U.S. Representative Sue Myrick, arguing that federal funds should be appropriated to states to assist DNA cases; Congressional Record, 2004).
The technology that has led to the use of DNA in criminal cases has opened up a new field for investigators in the United States. Some scholars have explained that DNA technology has produced nothing short of a revolutionary breakthrough in the criminal justice system. DNA technology has led to the prosecution of guilty suspects and has also led to the exoneration of those wrongfully convicted of felonies. This paper reviews cases where DNA was used to convict a rapist and murderer, and cases where a previously convicted rapist was exonerated.
Post-Conviction DNA Testing and Exoneration Statistics
According to the Columbia Law Review (Garrett, 2008, p. 58), as of 2008, forty-three states and the District of Columbia had put legislation on the books offering access to post-conviction DNA testing. Six states have founded "innocence commissions" whose task is to investigate cases in which a person may have been wrongfully convicted. Meanwhile, the U.S. Congress passed the DNA Analysis Backlog Elimination Act in 2000, providing funds to help states advance their DNA technologies. In 2004, Congress also passed the Innocence Protection Act, which encourages DNA testing of those convicted of capital crimes (Garrett, 58).
Exonerations in the U.S.: 1989 Through 2003
An article in The Journal of Criminal Law & Criminology reports that in the fifteen years between 1989 and 2003, there were a total of 340 exonerations in the United States criminal justice system. Of those — 327 men and 13 women — 144 were cleared of wrongdoing through the application of DNA technologies, and 196 were exonerated through other means (Gross, et al., 2005, p. 524).
More than half of those exonerated had served at least ten years in prison, Gross continues, and prosecutors do not always admit they were wrong in convicting a person later proven innocent through DNA analysis. For example, Gross notes that Charles Fain was exonerated thanks to DNA research in 2001 in the state of Idaho. He had spent eighteen years on death row, wrongly accused of a rape-murder. The prosecutor uttered this statement after Fain was released from prison: "It doesn't really change my opinion that much that Fain's guilty" (Gross, 526).
Another example of a prosecutor refusing to admit a mistake occurred in DuPage County, Illinois, in 1995. Alejandro Hernandez had been convicted for an abduction, a rape, and a murder that he had nothing to do with. All charges were dismissed against Hernandez — who had been in prison for eleven and a half years — when DNA tests and a confession by the real killer, an imprisoned serial rapist and murderer named Brian Dugan, were brought forward. The police officer who had supplied "crucial evidence" admitted he had lied about Hernandez, and DNA proved Hernandez was not guilty. Still, the prosecutor stated: "The action I have taken today is neither a vindication nor an acquittal of the defendant" — a remarkably arrogant statement in light of the empirical DNA evidence that set Hernandez free after eleven and a half years of wrongful imprisonment (Gross, 527).
As DNA technologies have advanced, the number of exonerations has increased. Between 1989 and 1994, there was an average of 12 exonerations per year due to DNA testing; since 2000, that average has risen to 44 exonerations per year as a result of DNA testing (Gross, 527). Gross provides noteworthy data indicating that ninety-six percent of the exonerations his research uncovered involve defendants wrongfully convicted of murder (60%, or 205 of 345 cases) or of sexual assault or rape (36%, or 121 of 340 cases). The remaining exonerated cases involved robberies, attempted murder, kidnapping, and assault.
Conclusion: The Case for Expanding DNA Testing
There are myriad cases in the literature demonstrating how DNA testing can turn the tide, either toward guilt or innocence. James Welsh writes in the peer-reviewed journal The Lancet that Ronald Jones certainly benefited from DNA testing. A Chicago court sentenced Jones to death in 1989 for rape and murder; the evidence used was a "confession" that Welsh explains was extracted from him while he was "under duress" (Welsh, 2000, p. 840). Subsequent DNA testing clearly established that "the semen found in the victim could not have come from him," and Jones was granted a new trial at which he was acquitted and released (Welsh, 840).
Moreover, as author Michael Risinger explains, those who believe the criminal justice system "rarely convicts the factually innocent" are not basing their judgment on "any empirically justified" facts (Risinger, 2007, p. 761). What needs to happen in the United States is that every state should be provided with adequate facilities and technologies to verify — through empirical DNA testing — that every rapist and murderer sentenced to death row was truly guilty.
Works Cited
Connors, Edward. (1996). Convicted by Juries, Exonerated by Science: Case Studies in the Use of DNA Evidence to Establish Innocence After Trial. Darby, PA: DIANE Publishing.
Dresser, Rebecca. (2011). Families and Forensic DNA Profiles. Hastings Center Report, 41(3), 11–12.
Garrett, Brandon L. (2008). Judging Innocence. Columbia Law Review, 108(1), 55–142.
Gross, Samuel R., Jacoby, Kristen, Matheson, Daniel J., Montgomery, Nicholas, and Patil, Sujata. (2005). Exonerations in the United States 1989 Through 2003. The Journal of Criminal Law & Criminology, 95(2), 523–560.
Myrick, Sue. (2004). Providing for Consideration of H.R. 6107, Justice For All Act of 2004. The Congressional Record. Washington, D.C.: Government Printing Office.
Risinger, Michael D. (2007). Innocents Convicted: An Empirically Justified Factual Wrongful Conviction Rate. The Journal of Criminal Law & Criminology, 97(3), 761–806.
Welsh, James. (2000). Death Penalty Suspended in Illinois. The Lancet, Vol. 355, p. 840.
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