I wonder if this unidentified girl might be Margaret Kay Holst, age 18, who disappeared from Omaha, Nebraska on 4 August 1977.
View a photo of Margaret Kay Holst, 18, missing 4 August 1977 from Omaha, NE at:
http://www.doenetwork.org/cases/2589dfne.html
View a composite sketch of an unidentified homicide victim from 1977 (Courtesy of Snohomish County Sheriff's Office) at:
http://www.theheraldbusinessjournal.com/article/20080501/NEWS01/97575371/0/images
LINK to Margaret's thread on Websleuths Missing Forum:
NE NE - Margaret Kay Holst, 18, Omaha, 4 Aug 1977 - Websleuths Crime Sleuthing Community
Thanks for the post, Richard! Margaret has been mentioned before....she is not on the rule out list...but there was some discussion about the distance creating a low level probable match.