Of course it is terrible that this happened - but the girl shouldn't have been going off alone with three men she barely knew. I'm not trying to say she deserved to be murdered or anything, but she made a very irresponsible choice.
Whether you are in Aruba or Anytown, USA getting into a vehicle with one man you don't know, let along three - is extremely foolish and risky.
Did the parents know there would be so few chaperones? I wouldn't have let my girls go on a trip like this. Why do teenagers need a big vacation just for graduation high school anyway? Senior trips have gotten way out of hand. In my day, the senior trip was an afternoon at
Disneyland.