TRACE EVIDENCE

TRACE EVIDENCE
DNA, Cold Cases, and the Hunt for Violent Predators
A True Crime Files Collection

For decades, they believed they had escaped.

Investigations stalled. Witnesses disappeared. Evidence sat untouched inside aging storage boxes while families waited for answers that never came. Detectives retired. Headlines faded. Violent predators vanished into ordinary life, protected by time and the limitations of the era in which their crimes were committed.

Then forensic science changed everything.

Trace Evidence brings together three chilling True Crime Files investigations connected by one terrifying reality: modern DNA analysis reopened cases once believed permanently unsolved.

Through preserved biological evidence, evolving forensic technologies, and the relentless pursuit of justice, these investigations reveal how science exposed violent offenders long after they believed the trail had gone cold forever.

Inside this collection:

A serial predator stalked Northern California for years, targeting women across suburban communities while investigators struggled to identify the man responsible. As fear spread and leads collapsed, the offender disappeared into anonymity. Decades later, advances in forensic DNA technology would reopen the investigation and expose the hidden trail he left behind.

In the winter of 1982, two young women vanished after hitchhiking through the Colorado mountains. Their murders remained unsolved for decades while investigators searched unsuccessfully for the killer responsible. Years later, preserved evidence and modern DNA science finally brought the cold case roaring back to life-leading investigators toward a suspect who had spent years living unnoticed in plain sight.

One of Texas's most haunting unsolved murder investigations began when four teenage girls were brutally killed inside an Austin yogurt shop in 1991. The case produced false starts, disputed confessions, legal controversy, and decades of unanswered questions. As forensic science evolved, investigators returned repeatedly to the evidence, searching for biological traces capable of revealing what happened inside the store that night.

More than a collection of true crime investigations, Trace Evidence explores the transformation of modern forensic science itself. From the birth of DNA fingerprinting to the rise of CODIS and genetic genealogy, these cases demonstrate how violent offenders increasingly found themselves trapped by the very evidence they believed time had erased.

This collection also includes exclusive omnibus material, including:

• The Evolution of DNA Forensics
• CODIS and Genetic Genealogy Explained
• A Forensic Terminology Guide
• Timeline of Major Forensic Breakthroughs
• Expanded Sources and Recommended Reading

Written in the investigative, cinematic style of the True Crime Files series, Trace Evidence combines forensic science, criminal psychology, and modern cold case investigation into a single premium collection examining how biology, technology, and persistence reshaped the pursuit of violent predators.

Because even after memories fade, the evidence remains.

A fingerprint.

A blood sample.

A strand of DNA.

Trace evidence.