• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar
  • Skip to footer
RedLawList.com

RedLawList

Straightforward, actionable information for life’s common legal matters

  • Home
  • Blog
  • Knowledge Center
Home / Knowledge Center / How Accurate is DNA Testing for Crimes in Cold Cases?

How Accurate is DNA Testing for Crimes in Cold Cases?

dna testing for crimes

DNA is often collected from a suspect and compared to evidence found at the scene of a crime. The ability to extract and analyze DNA became useful to law enforcement agencies desiring to identify criminal suspects or to prove someone’s innocence. While enhancing investigators’ crime-solving ability, forensic science is not without error and drawbacks.

The science behind DNA evidence

Nuclear DNA (nDNA) is found in various body fluids, bones, hairs and skin cells. DNA is commonly found in shed hairs, skin cells, fluids or on surfaces touched or worn by individuals. The genetic material may be further categorized as Y-chromosome DNA, which is specific to men and passes from father to son. On the other hand, mitochondrial DNA (mtDNA) passes from mothers to their children.

By analyzing DNA samples, sequences and chromosome information, scientists are able to determine if the material came from a man or a woman. The unique sequence is also used to differentiate DNA samples between suspects and victims.

Polymerase chain reaction (PCR) techniques require far less DNA compared to the sample size required for RFLP testing. However, any contamination cancels verification possibilities.

Short tandem repeat (STR) analysis technology assesses specific regions (or loci) on nuclear DNA.

Is DNA testing accurate?

Traditional fingerprinting and eyewitness testimonies are riddled with flaws. Thus, DNA samples derived from crime scenes and suspects are an invaluable part of forensic evidence. In order for DNA evidence to be accurate, investigators must collect samples and handle them appropriately.

Forensic technicians must then use an accepted methodology to analyze the samples. Scientists estimate that there is a one in a billion chance that one individual’s DNA sequence matches another individual’s sample. Thus, DNA forensic evidence is thought to have a 95 percent degree of accuracy.

The potential for error

However, human error has the potential to diminish the accuracy of DNA evidence. If not obtained and handled properly, DNA samples may become contaminated with the DNA of investigators or laboratory technicians. Lab techs must also have the ability to properly analyze samples, which might include material from more than 1 person.

Samples collected might also endure environmental damage through exposure to extreme temperatures or other factors.

Unfortunately, some samples might prove too minuscule in order to provide satisfactory sequencing. Individual states have specific requirements, which if not met regarding the evidence, may lead to objections by defense attorneys and subsequent evidence dismissal by judges.

DNA applications in cold cases

The advancements in DNA technology enhance law enforcement officials to solve older, or “cold case,” files. Early DNA analysis involved a technique known as restriction fragment length polymorphism (RFLP). But the process required large quantities of DNA in samples in order to ensure accurate results. Contaminated samples also prohibit proper analysis. Thus, the method is not a viable option for solving cold cases.

However, PCR and STR methodologies enable forensic scientists to establish profiles based on biological evidence. Clothing, weapons and other objects collected from original crime scenes may harbor cells containing DNA, which is suitable for analysis.

While various cold case files have been solved using DNA evidence, the likelihood of error is always present. Thus, suspects and defense attorneys are wise to exercise a healthy skepticism and carefully weigh the evidence for refutability.

Related resources

  • why preserving evidence is important
    The Importance of Preserving Evidence in Criminal Cases
  • Dangerous cities in Texas
    5 Most Dangerous Cities in Texas
  • steps for federal crimes
    11 Steps in the Federal Criminal Justice System

Primary Sidebar

Find an attorney at ENJURIS.COM

Legal Topics

  • Accidents & Injuries
  • Criminal Law
  • Defective Products
  • Insurance Disputes
  • Legal News
  • Workers' Compensation

Must Reads

  • Understanding the Alternatives to Foreclosure
  • What Can I Expect at a Mediation Session?
  • Why Having a Business Succession Plan is Important
  • 5 Legal Concerns for Owners of Waterfront Property

Blogroll

  • Attorney Web Marketing
  • The Babcock Law Firm
  • Lawteryx: The Legal T-Rex
  • Workers' Comp Lawyers: Gerber & Holder
  • American Bar Association
  • Cornell Legal Encyclopedia
  • SCOTUS Blog
  • Volokn Conspiracy

Legal Directories

  • Enjuris: Directory for Personal Injury Lawyers
  • Martindale
  • Find Law
  • Cornell Lawyer Directory

Footer

RSS Enjuris Law Blog

  • How Lower Speed Limits Could Affect Your Injury Lawsuit
  • What is the Montreal Convention?
  • 2025 Nutribullet Lawsuit Alleges Explosion Injuries
  • Who’s Liable When Heat Turns Dangerous?
  • Team USA Judo Coach Arturas Lanchinskas Files Lawsuit After Scalding Coffee Incident

RSS Legal Week

  • Boar’s Head Faces Lawsuits Amidst Massive Listeria Recall
  • New Study Links Fatal Lung Disease Silicosis to Quartz Countertops
  • What is Strict Liability & How Does It Affect Colorado Personal Injury Cases?
  • Colorado 911 Operators Now Covered by Workers’ Comp for PTSD
  • New Colorado Law Extends Workers’ Comp Reporting Time

RSS Lowering the Bar

  • Sea-Cucumber Abuser to Be “Moved Far From the Sea for a Long Period of Time”
  • Defendant Recruited Seven Actors to “Testify” in Fraud Trial
  • Assorted Stupidity #169
  • Justice Harlan on Dirty Movies: “By Jove! Extraordinary!”
  • Authorities Question Unlicensed Beaver Releases

© 2025 RedLawList. All rights reserved.