Cold fact: Uncovering the blanket of evidence

Kari Danser, MS, Matthew M. Legler, and Mark W. Perlin, PhD, MD, PhD, "Cold fact: Uncovering the blanket of evidence", Promega's Thirty Sixth International Symposium on Human Identification, West Palm Beach, FL, 5-Nov-2025.

Poster

Download Poster

Abstract

On the night of June 13, 1963, a white car pulled up to an Enco gas station on an old Wisconsin highway. Oshkosh station owner Wayne Pratt went over to assist. The station lights suddenly went dark. Pratt’s wife later discovered his body in a storage room, hidden beneath a blanket. He had been stabbed over 50 times.

Despite questioning 75 people and administering 25 lie detector tests, investigators couldn’t uncover any solid leads. The absence of physical evidence and eyewitnesses stalled the homicide investigation. The case went cold and remained dormant for decades.

In 2012, Winnebago County reopened the investigation. The Sheriff’s Office sent the blanket to the local crime lab for DNA testing, but the lab gave inconclusive results. Private forensic labs retested the blanket in 2015 and 2023, uncovering a degraded, low-level DNA mixture of multiple people. But they couldn’t interpret the complex mixture. The blanket DNA evidence remained inconclusive.

In April 2024, the Sheriff’s Office sent the blanket DNA data files to Cybergenetics. Applying its TrueAllele® technology to the data, the company analyzed the degraded three-person mixture. The computer separated the STR data into three distinct genotypes.

The blanket’s probabilistic genotypes were compared with multiple suspect references, and a DNA identification was made. In June, Cybergenetics issued a report that statistically linked the blanket to suspect William Doxtator.

This forensic science breakthrough, combined with original case reports and witness statements, led the Sheriff’s Office to refer a charge of First-degree Intentional Homicide to the District Attorney’s Office.

Sixty years after the crime, better DNA science had solved the case. Doxtator died in 2022. District Attorney Eric Sparr believed that, had he lived, the new DNA evidence would have justified a homicide prosecution.

This case highlights how a single technological advance—unmixing DNA mixtures—can transform forensic science, strengthen justice, and redefine human identification. A computer gave voice to previously silent evidence, showing how statistical innovation and human determination can bring resolution to even the coldest of cases.