Apologies if this was covered before...I was out preparing for this snowstorm we're getting
The only thing that makes sense to me regarding Sarai's missing clothes is that the perp wanted to remove any evidence that could contain DNA, fingerprints, etc. that's why only her shell was taken, in other words, anything the perp would have touched.
And this fact also removes the druggie attack as possibility. A druggie would not remove her clothes and leave behind the jewelry. Even in a possible rape, the druggie would not take off her shoes. Why would he have to?? He just needs to pull down her pants not take them off.
Somebody that she casually met during her time there could have picked her up in a car during her walk. She was a very trusting person. She would have not given it a second thought to jump in a car with someone who she previously shared a brief exchange with. Perhaps even someone who saw her in the bar the night she had the encounter with Tarkan.
Anyway, that's what I got thus far...