Martha L. Hardin, called Mardi by family, was 34 when she disappeared from Muskegon Heights, Michigan, in the summer of 1985.

The Muskegon Police Department opened the investigation under case numbers 85-23540 and 03-27118. Over time the case went cold, and investigators and family shifted toward forensic options: DNA from her sister and son has been uploaded to national databases in hopes of matching unidentified remains.

Anyone who knew Martha, her routines in Muskegon Heights in 1985, or who has any information that could help the family is asked to come forward.