I agree she has what appears to be a St. Christopher medal pinned to her, he is the patron saint of safe travel and journeys.
In addition I agree with everyone else's comments on here. No basic information.. i.e.
Did the entire bus go missing?
Did her travel companions say she never got on the plane to return home.
So the only thing it could be:
I believe a person that casually knew her and knew she was taking a church trip and never returned was the person that reported her missing. I also believe that person took her photo with the St. Christopher medal on her departure before she boarded the bus. Since that was last time she was seen. The medal is also casually pinned to her like it was temporary, it looks like she also wore another medal because that is a medal chain.
This person may be so casual no one will give them to much info, all they know or think is that she never returned.
Maybe she did return, maybe she did not. Or maybe she did not want this person to know and she moved some where else. Very sketchy missing report by someone that did not know too much.
Her family would have known if she didn't return in January 2017 and would have reported it then. She must have some relatives, even her church friends would have reported it if that was the case and the landlord. But no one did,
know one that really knows her reported her missing because they wouldn't wait until August 2017.
A church may not necessarily sponsor a tour, however there are plenty of catholic pilgrimages.
http://catholicjourneys.com/holyland.htm