RSBM
IMO it's not to suggest anything points to the ex-step-father based on where he dropped her off. It just seems weird. Also IMO it has nothing to do with trusting her to get herself to the airport, it's just a nice thing to do if you're already driving part way there. So if it was his idea - why wouldn't he just take her all the way? If it were her idea - why did she want to stop at the mall and then take transit? Maybe the agreement was to take her to the airport but something happened and someone made a change. Maybe she had plans to meet someone.
Anyway, for me it's just one of the few facts we have and it's interesting to think about and consider the possibilities.
JMO etc.
I can see it a couple of ways. The SD offers or agrees to take Katelin to the airport. At the last minute, Katelin says, "You know what, I really wanted to shop for a new xxxx before I go back, but didn't have a chance to get to the mall. I still have plenty of time before my flight. Why don't you drop me off at the mall, and I'll take the Metro to the airport."
My son often tries to squeeze in that one last thing before he leaves after a visit. My stepson used to do that, too. (For that matter, so does my 19-year-old niece, but she drives her own car.) I prefer to see my son off at the airport, but if he has a sudden change of plans and asks to be dropped off somewhere, say to meet a friend for lunch or dinner, with an alternate means of getting to the airport, it's not a big deal. At 19, being the kind of mom that I am, I probably would've worried that he'd get sidetracked and miss his flight, but I wouldn't have
insisted that my husband or I drive him. On the other hand, I don't know Katelin. If the scenario is totally out of character for her, then it's concerning. But judging by what I'd say is average for a 19-year-old, the SD's account is not suspicious in itself.
On the flip side, if we're just kicking around ideas, one could speculate the change of plans resulted after an argument that took place along the way, and Katelin looked for an excuse to get out of the car because she was upset.
I find both scenarios plausible, and neither necessarily implicates the SD. Whether there was an argument, or Katelin truly wanted to go shopping, he simply might have dropped her off near the mall, and from there something went wrong.
The text to her mother is what I find most puzzling. Was it voluntary? Was she forced? Was it really her? Again, it goes back to the cell records. They should be key in the way of answers.
I know Katelin's loved ones are frantic with worry, and I only pray that she returns home safely and very soon.