Authorities in Tennessee have matched a skull found in 2004 to a missing college student who disappeared in 1986.

Alice Mae Sullivan, 20, was declared missing on August 29, 1986, after she did not arrive to collect her 3-year-old son from a babysitter’s house, reported The Tennessean.

Sullivan was attending Tennessee State University and had gone to class on August 28 but failed to pick up her child. Her parents lodged a missing person report, according to WZTV.

The skull was found by a contractor on a home site in north Nashville on February 20, 2004.

The skull was analyzed at the University of North Texas Center for Human Identification and was identified as Sullivan’s. Investigators noted there was no trauma evident on the skull, and despite a comprehensive search, no other remains were discovered in the vicinity where it was located.

The investigation into Sullivan’s disappearance and death continues.