dna evidence

A 65-year-old man who appeared several times on America’s Most Wanted for a 1984 murder in Florida was recently arrested in California. According to news reports, Donald Santini had evaded authorities for almost four decades before law enforcement located him in San Diego. Santini is facing a charge of first-degree murder in the death of 33-year-old Cynthia Wood. Santini immediately fled the state after the police identified him as a suspect in Wood’s murder.

Santini’s arrest highlights how new developments in DNA technology can assist law enforcement in solving cold cases, particularly a DNA test in a murder trial. Keep reading to learn more about this technology and its admissibility at trial.

What Kind of DNA Technology Is Available Today Versus at the Time of the Murder?

DNA profiling, also known as DNA fingerprinting, emerged in the mid-1980s when the murder occurred. Although the reliability of early DNA testing was questionable, advancements in DNA technology during the 1990s and 2000s made DNA evidence common in criminal cases.

The first DNA testing method in criminal investigations, restriction fragment length polymorphism (RFLP), required large DNA samples for accurate testing. In the 1990s, polymerase chain reaction (PCR) testing emerged. This method requires a much smaller sample than RFLP testing. Other techniques introduced in the 21st century include single nucleotide polymorphism arrays and next-generation sequencing (NGS). Touch DNA can now identify someone’s genetic fingerprint with a microscopic sample, based on DNA that transfers upon contact with the tested subject.

What Evidence Would Be Admissible at Trial?

Chapter 23 of Title 44 of the Pennsylvania Code governs the collection and use of DNA evidence in police investigations. The statute requires the collection of DNA samples from any person convicted of a crime, adjudicated delinquent for a felony sex offense, or incarcerated for a felony sex offense or other specified offense. Under the law, the authorities may use these samples for identification purposes, to recover and identify human remains, or to identify missing persons.

Pennsylvania rules for DNA evidence in court must also meet the admissibility requirements under the Pennsylvania Rules of Evidence.

DNA evidence admissibility in court in Philadelphia will depend on the following factors:

  • Relevance – DNA evidence must tend to make a fact more or less probable than without the evidence, and that fact must have a material effect on the outcome of the criminal case.
  • Reliability – A party using DNA evidence must prove the reliability of the DNA testing, including by showing that the testing complied with generally accepted scientific principles.
  • Authenticity – The authenticity of DNA evidence in a criminal case must be established, typically by proving an unbroken chain of custody of the DNA samples used in testing.

Was Any of the Old Science Debunked Since its Running?

Although modern DNA testing techniques perform analysis much more quickly with smaller samples than older techniques, many historical testing techniques remain scientifically reliable. However, older methods can be unreliable due to small or degraded DNA samples or samples that contain DNA from multiple contributors.

Do They Have Any DNA Evidence with Integrity Today?

One of the biggest challenges to solving old cases with new DNA testing technology involves the quality of old DNA samples. DNA samples will degrade over time in storage. Newer testing techniques can perform reliable analyses even with smaller or previously degraded samples.

Can Law Enforcement Re-Run Old Evidence with Today’s Tech?

Law enforcement can regularly re-run old DNA evidence as new testing technologies become available. However, many crime laboratories suffer from significant case backlogs, delaying or preventing re-testing of old evidence unless investigators, convicted defendants, or victims’ families push crime labs to re-test evidence.

What Can Someone Do If They Are Facing Criminal Charges Based on Old DNA?

If you or a loved one is facing criminal charges for a crime for which law enforcement is using old DNA, it’s essential you hire an experienced criminal defense lawyer who understands DNA technology and the rules of evidence regarding its admission at trial. In some cases, old DNA may exonerate you or provide a basis for challenging the charges against you. Contact The Zeiger Firm to speak to a knowledgeable Philadelphia criminal defense lawyer.


Brian J. Zeiger, Esquire, is an experienced and successful criminal defense and civil rights attorney. He is a seasoned trial lawyer with significant experience before juries and judges. Brian understands civil rights cases, including Taser, Wrongful Death, Excessive Force, Police Brutality, Police Misconduct, Malicious Prosecution, Monell Claims, Sexual Assault, Prisoner’s Rights, Time Credit, Medical Malpractice, and Medical Indifference.