Using DNA Evidence to Overturn a Conviction in PA

When someone is wrongfully convicted of a crime they didn’t commit, it can be absolutely devastating – for the innocent person, their family, the victim’s family, and the community. Thankfully, advances in DNA technology have made it possible to conclusively prove innocence in some cases, even decades after a conviction.

In Pennsylvania recently, three men – Derrick Chappell, Morton Johnson, and Samuel Grasty – who were convicted in the 1990s of murdering an elderly woman have brought forward new DNA evidence that they say proves their innocence. They’re hoping this evidence will lead to their convictions being overturned after spending over 20 years in prison.

The Crime and Original Convictions

In 1997, 70-year-old Henrietta Nickens was sexually assaulted and murdered in her home in Chester, PA. At the time, the prosecution’s case relied heavily on the testimony of a teenager named Richard McElwee, who had intellectual disabilities. He implicated himself and the three defendants in the crime, although his account was inconsistent. All three men maintained their innocence but were convicted in separate trials in 2000 and 2001.

There was semen collected from the crime scene that didn’t match any of the defendants. However, the prosecution argued it wasn’t connected to the murder and didn’t change the other evidence used to convict them.

The New DNA Evidence

In 2021, new, more advanced DNA testing was done on evidence from the crime scene, including the semen sample. This testing found that the semen matched other crime scene evidence – including more semen on the victim’s jacket and bedsheet. This provides a much stronger link between the semen and the actual perpetrator. At the same time, it excludes Chappell, Johnson, and Grasty as matches.

According to the defendants’ attorneys, this evidence clearly points to another unknown man as the true killer. It strongly suggests this was a solo crime committed by one perpetrator – not multiple people as the prosecution claimed at trial. They argue it’s impossible the victim was having consensual sex beforehand with some mystery man, as prosecutors have suggested.

“This 70-year-old woman in bad health was having consensual anal sex with someone who came over to her house to do cocaine? It’s preposterous, outlandish, offensive, yet this is what they’re doing,” said Vanessa Potkin, attorney for Morton Johnson.

The Legal Process

In July 2022, the three men appeared in court in Delaware County, PA for the start of hearings on their appeals. Their attorneys are asking the judge to vacate their convictions and order new trials based on the DNA evidence. The prosecution is opposing this and arguing the original convictions should stand.

At the July hearing, both sides gave opening statements. The defense presented testimony from a forensics expert about the DNA analysis. The case is set to resume on August 22, when the prosecution will get to present counter evidence.

According to Pennsylvania law, people seeking to overturn their conviction based on new evidence must file something called a Post-Conviction Relief Act (PCRA) appeal. This happens in the original county court that handled the case.

Possible Outcomes

• The judge grants a new trial – This would allow a new jury to hear the case with the DNA evidence.
• The judge overturns the conviction without a new trial – If the DNA evidence is strong enough, the judge could vacate the conviction entirely without a retrial.
• The judge rejects the appeal – The convictions would stand and the men would remain in prison.

The attorneys for Chappell, Johnson, and Grasty say they are hopeful the DNA evidence will finally lead to their clients being exonerated. But getting wrongful convictions overturned can be incredibly difficult, even with compelling new evidence.

Impact on Victims and the Community

When someone is exonerated years after being convicted, it can be very painful and confusing for the victim’s family and community. The victim’s family may feel like they are going through the trauma of the crime all over again.

It also means the search for the real perpetrator has to start over. The unknown man whose DNA was found would still be out there somewhere. For the community, it means coming to terms with the fact the justice system made a terrible mistake.

At the same time, if innocent people have been imprisoned, the victim’s family may want more than anyone to see justice served properly. Henrietta Nickens’ family has not spoken publicly about this case.

Why Wrongful Convictions Happen

There are many reasons why wrongful convictions occur. Some common causes include:

• Eyewitness misidentification – When a witness mistakenly identifies the wrong person as the perpetrator.
• False confessions – When someone confesses to a crime they didn’t commit, often due to coercion.
• Misconduct by prosecutors or police – Such as concealing exculpatory evidence that would show innocence.
• Unreliable informants – When prosecutors rely on testimony from jailhouse snitches or others with incentives to lie.

Many experts say that misconduct by prosecutors and police is a major factor in wrongful convictions. There have been calls for reform, such as requiring prosecutors to share more evidence with the defense. But progress has been slow in many jurisdictions.

Fighting Wrongful Convictions

The good news is that thanks to advances in DNA technology and the tireless work of advocates, more wrongfully convicted people are being exonerated today than ever before. There are also an increasing number of “innocence organizations” devoted to investigating and overturning wrongful convictions.

Some of these include:

• The Innocence Project – A national organization that has helped exonerate hundreds, and advocated for reforms.
• The Pennsylvania Innocence Project – Helps PA prisoners through DNA testing and legal assistance.
• The Innocence Network – An affiliation of innocence projects working on wrongful convictions.

Pennsylvania has also passed some reforms in recent years, including improving access to post-conviction DNA testing. But there is still a long way to go. The case of Chappell, Johnson and Grasty underscores the urgent need for Pennsylvania and states across the U.S. to work harder to prevent wrongful convictions in the first place.