Having lived in both CR and Nicaragua, I can comment on this a little. Costa Rica is actually not that safe. Nicaragua prior to this year was safer. While people don't generally disappear, in the cases of home invasions (happens a decent amount in CR) and robberies, about 75% of the time there was some sort on involvement with security or guards. Usually some sort of set up. People weren't usually hurt although I can definitely recall rape occurring at least once.
When I lived in Nicaragua the power went out fairly frequently. I remember the first time it did I went outside and my landlady flipped out at me because that is the time you will tend to be attacked. She told me that is when I need to sit inside and make sure my door was locked. Now this was considered at the time a relatively safe time, especially in comparison to CR.
Like I said I have no idea what could have happened, but wandering around with all your luggage makes you a huge target for robbery at the very least. I highly doubt this is human trafficking, there are tons girls from about 12 years and up who work as prostitutes in CR and Nicaragua. They are everywhere if you have ever visited and/or lived in either country.
