A major breakthrough has finally been made in one of Frederick’s most haunting cold cases. After nearly four decades of unanswered questions, investigators have identified the killer responsible for the 1988 murder of Delores Marie “Mooda” Thompson, bringing long-awaited closure to a case that has weighed heavily on the community and on Thompson’s loved ones for almost 40 years.
The City of Frederick announced the development on Friday, marking a significant milestone in the pursuit of justice. According to the Frederick Police Department, Calvin Ziegler was conclusively identified as Thompson’s killer through advanced DNA analysis.
While Ziegler passed away in 2010, he had been interviewed multiple times during the original investigation but was never charged due to the limitations of forensic science at the time.
With DNA technology still in its early stages during the late 1980s, investigators were unable to match the evidence found at the crime scene to any known suspect.
The case began on February 1, 1988, when Thompson was discovered deceased in her apartment located in the 100 block of South Market Street. Her death was quickly ruled a homicide, the result of ligature strangulation.
Additionally, further examination revealed that she had been sexually assaulted, a devastating detail that underscored the brutality of the crime. Although evidence was collected from the scene, the forensic tools available then were not advanced enough to yield a reliable match, leaving investigators with leads but no concrete suspect.
For years, Thompson’s family, friends, and the community lived without answers, as the investigation gradually grew cold. However, in 2025—nearly four decades after the crime—detectives and the Crime Scene Unit took a fresh look at the case.
During this re-examination, they identified a small piece of bedding that had never before been tested. This previously overlooked sample provided the crucial link. When analyzed using modern DNA testing methods and compared against entries in both state and national CODIS databases, the results pointed unmistakably to Ziegler.
Following this discovery, the Frederick County State’s Attorney reviewed the findings and confirmed that Ziegler was indeed responsible for Thompson’s murder. With this confirmation, the case was officially closed, bringing long-awaited answers to a tragedy that had gone unresolved for far too long.
In a statement acknowledging the emotional impact of the development, the Frederick Police Department expressed its compassion and support:
“The Frederick Police Department extends its deepest sympathy to the family and friends of Delores ‘Mooda’ Thompson. We ask that the family’s privacy be respected at this time as they process this development.”
While Ziegler’s death means he will never face justice in a court of law, the conclusion of this decades-old investigation provides a sense of closure that many believed might never come.
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