The Wrongful Conviction of John Kunco

In 1991, a brutal assault inside a Pennsylvania apartment set off an investigation that would ultimately expose deep flaws in forensic science — and leave lasting questions about justice.

John Kunco, a former maintenance worker at the victim’s apartment building, was convicted of raping and torturing a 55-year-old woman. The crime was horrific. The pressure to identify a suspect was intense. But the evidence used to convict Kunco was far from conclusive.

There was no DNA evidence tying him to the scene.

Instead, the prosecution’s case rested largely on two things: an alleged bite mark found on the victim’s shoulder, and a delayed voice identification that only solidified after police attempted to imitate the attacker’s speech.

An Investigation Built on Assumptions

In the immediate aftermath of the attack, Pennsylvania State Police processed the crime scene and collected physical evidence, including bedding, clothing, hair samples, and a sexual assault kit. Fingerprints recovered from the apartment were unusable, and laboratory testing failed to identify biological material linking Kunco to the crime.

In fact, hair found at the scene excluded him as a contributor.

Despite these findings, investigators focused on Kunco due to his prior access to the building. While hospitalized, the victim told police the attacker’s voice sounded like someone named “John” who had previously worked there. She did not initially identify Kunco as her attacker.

That changed only after a detective later attempted to imitate the attacker’s voice — including a lisp — during a hospital visit. It was after that interaction that the victim became convinced Kunco was responsible.

The Bite Mark Evidence

With no physical evidence placing Kunco inside the apartment, prosecutors turned to bite mark analysis.

Two forensic dentists testified at trial that an injury on the victim’s shoulder matched Kunco’s teeth to a “reasonable degree of dental certainty.” Their conclusion was based on photographs taken without a measurement scale and an in-person examination conducted five months after the injury had healed. Using ultraviolet light and hand-drawn overlays of Kunco’s teeth, the experts told jurors they could identify him as the biter — and exclude everyone else.

That testimony proved decisive.

Kunco was convicted and sentenced to decades in prison, despite presenting an alibi supported by his girlfriend and corroborated by phone records and handwritten notes from his former employer.

Science Catches Up

Years later, advancements in forensic science began to unravel the case.

In 2009, post-conviction DNA testing was conducted on an electrical lamp cord used during the assault. The results excluded John Kunco as the source of DNA found on the cord. Still, the court denied relief, citing the bite mark evidence and other circumstantial testimony.

The turning point came in 2016.

That year, the two forensic dentists who had testified at Kunco’s trial submitted a joint affidavit acknowledging that they no longer stood by their original conclusions. Updated guidelines from the American Board of Forensic Odontologists now prohibit experts from making individual identifications based on bite marks. Under current standards, an expert can no longer say that a specific person made a specific bite mark — only that someone may or may not be excluded.

Additional forensic experts, including leadership within the odontological community, testified that bite mark analysis lacks scientific reliability and should not be used in criminal investigations.

A Conviction Vacated — But Questions Remain

On May 23, 2018, a court in Westmoreland County, Pennsylvania, vacated John Kunco’s 1991 conviction. By then, he had spent nearly 28 years in prison.

The ruling acknowledged the collapse of the forensic evidence used to convict him, including the bite mark testimony and DNA exclusions that pointed away from Kunco and toward an unknown assailant.

But the case did not end cleanly.

Following his release, Kunco faced new criminal allegations unrelated to the 1990 assault. He later entered guilty pleas to reduced charges, including pleas connected to the original case, in exchange for credit for time served. Those decisions complicated public understanding of whether Kunco was wrongfully convicted — raising difficult questions about legal strategy, risk, and the realities faced by someone who had already lost decades of their life behind bars.

What those pleas did not change was the forensic record.

DNA evidence excluded Kunco from key physical evidence. Bite mark testimony — once presented as scientific certainty — has since been discredited. And biological evidence from the crime scene pointed to someone else, a person who has never been identified.

As of today, no one else has been arrested or charged in connection with the assault of Donna Seaman.

A Tragic Ending

John Kunco did not have much time to live as a free man. He passed away in August of 2025 at the age of 60 after a battle with cancer.

His case remains a sobering example of how flawed forensic methods can shape investigations, influence juries, and alter lives — even when later science tells a different story.

Why This Case Still Matters

Wrongful convictions don’t always stem from bad faith or intentional misconduct. Often, they arise when unproven techniques are treated as fact, when expert testimony goes unchallenged, and when the appearance of certainty outweighs scientific reality.

The case of John Kunco forces us to confront uncomfortable questions about how justice is determined — and how easily it can be distorted.

Because in forensic science, the difference between possibility and proof can mean the difference between justice and injustice.