no grounds: What the heck took them so long? They arrested two guys who ended up probably just being in the wrong place at the wrong time: rich vs. poor.
They were not just in the wrong place, the wrong time. They were considered persons of interest and suspicious since they were in the habit of offing American girls, the thugs.
not necessarily. there were plenty of people who came forward and told the cops that these two guys always skullked around the pool at the hotel and the local bars and tried to pick up tourists. but they also could have been holding these guys to make the real perps think they were home free. you never know.