Margaret Elaine Diaz, also known by her maiden name Margaret Cohen and a former married name Margaret Riley, was last seen in Tacoma, Washington, on July 4, 1988, during a family gathering for her 32nd birthday. A mother of three, she was described as biracial with dark brown hair, green eyes, about 5 feet 5 inches tall and 125 pounds. The family celebration is the last confirmed sighting; it is not known what she was wearing that day or whether she left the event alone or with someone else.

The case file notes Margaret had connections in the Hilltop area of Tacoma and was described as having a high-risk lifestyle, yet it was considered uncharacteristic for her to cut off contact with her children, with whom she normally communicated regularly. The Pierce County Sheriff’s Office continues to list the disappearance as an open investigation, and her NamUs entry is MP10584.

The limited public details and the absence of clear leads have left her family without answers for decades. If anyone knew Margaret, saw her in Tacoma around July 4, 1988, or has information about her movements that day, please contact the Pierce County Sheriff’s Office.