Ug, that's hard. I'm so sorry.
I remember in high school getting a note from one of my friends that someone we both knew had gone out jogging and never came home. I wasn't close to the family, but I knew them, and watching them going through it all was hard. And I remember the day they publicly gave up hope. Though I wouldn't be surprised if a tiny bit of them still wonders in the back of their mind if their daughter might show up one day.
I found this article about the girl. Just looking at the one iconic photo that was everywhere back then brings up so many memories. https://charleyproject.org/case/tera-lynn-smith