Do you happen to know if Denise had joined a sorority and if all these girlfriends looking for her are also members? Is anyone able to share where she was on Monday and Monday evening?
General thinking:
Dad first said she was in the shower when he left for work and her brother was sleeping, which would mean no one actually saw her. Then he said they had a conversation before he left. Are these two parts of the same story (they spoke, then she got in the shower and he left) or is the story changing?
If the neighbor sighting is true, the image it brought up for me was Denise sitting on the curb waiting for a ride. She has plenty of friends who haven't spoken up about her missing, and could easily have contacts that no one knows about. If sh was picked up by someone and that someone did her harm, they obviously wont be coming forward.
I lean toward self harm as well and believe that is what s driving her friends to search wooded areas. They aren't doing that because they think she is lost. Losing a mom is incredibly hard, especially with her boyfriend out of state and if she has struggled with depression or has other stresses.