Frederick Police Announce Cold Case Breakthrough in 1988 Homicide of Delores “Mooda” Thompson

Watch the full announcement from Chief Lando and our investigative team in the video here.

The Frederick Police Department today announced the identification of the person responsible for the 1988 homicide of Delores Marie "Mooda" Thompson (DOB: Oct. 12, 1964). Ms. Thompson was found deceased in her apartment in the 100 block of S. Market Street on February 1, 1988. Her family and friends have long lived without answers; this development provides them long-awaited clarity.

An examination of the original investigation found that Ms. Thompson's manner of death was ligature strangulation and that the case included evidence of a sexual assault. At the time of the original investigation in 1988, forensic DNA testing was in its infancy, and no evidentiary samples produced an identifiable suspect profile. Multiple individuals, including Calvin Ziegler, were interviewed in 1988; Ziegler was known to the victim and frequently visited the victim's apartment. No suspect sample was ever developed from the evidence available at that time.

In 2025, detectives and Crime Scene Unit personnel conducted a methodical re-review of the physical evidence using updated forensic techniques and departmental equipment. Crime Scene Specialist Sabrina Swann identified a small area of bedding not previously tested. Modern processing of that material produced a DNA profile eligible for state and national CODIS comparison, which returned a hit to convicted offender Calvin Ziegler. Ziegler died in 2010.

The Frederick County State's Attorney's Office reviewed the forensic findings and issued a formal letter confirming that the evidence supports the identification of Ziegler as the contributor of the DNA and the person responsible for Ms. Thompson's homicide. Because the identified individual is deceased, criminal charges are not possible; however, the case will be listed as closed based on the evidentiary findings.

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.

For more information regarding today's announcement and to hear directly from our investigators, please watch the video here.