If we are to believe the ex who saw her stuff on the bed, it would be unusual for her to put her own belongings there like that.
But that makes things extra strange. No kidnapper is going to collect her belongings and put them on the bed. No rapist or murderer, either.
Either she put the belongings on her bed herself or a not-very-sophisticated perp did, as staging. Why?
The only reason that comes to mind easily is that the person was trying to fill in a story about what took place at the residence instead of what really happened. So the real story that took place at the residence would throw too much suspicion on the perp, apparently.
In other words, it's someone she knows, and she voluntarily spent time at the residence with him/her before she went missing. Also, the perp isn't the brightest bulb on the string
All mho, of course.
ETA: Ooooh, or she was never at the residence at all, and the staging was to make it appear that she had been.
My big point is that the items being there was staging, and the reason for the staging points to who did it. (Or the ex was wrong, and she dumps out her purse on her bed or something sometimes. The family and friends will have to decide that.)