Updated

TACOMA, Wash. -- A hiker's discovery of a skull near Mineral has revived a murder mystery from the 1980s, and sheriff's detectives from Lewis and Pierce counties are taking another look at the deaths of two couples.

The skull found March 26 was identified as the remains of Michael Riemer of Puyallup. He disappeared in December 1985 with his girlfriend Diana Robertson. Her body was found several months later. Their 2-year-old daughter had turned up alone in a Spanaway store on the day they were last seen alive.

In August of 1985 a Tacoma couple, Steven Harkins and Ruth Cooper, went camping in southern Pierce County and were later found dead.

The News Tribune reports the women, Robertson and Cooper, both had tube socks tied around their necks.

The killings remain unsolved.