I think the tourism/government would care about crime that is directly linked to the bread and butter (hotels, resorts, high end restaurants) but not so much travel between the resort areas. Outside of high tourist dollar areas, I think little attention is paid to crime. I have students and friends who visit family in the cities and countryside of the DR. To a one, they say that you have to be careful at night, never travel alone, and look out for roving moped/motorcycle groups who smash and grab or attack in a group. While this was not the case as far as we know for this couple, there may be some connection to a robbery or other crime that they experienced but the information seems so cloudy and confusing that we will probably never know.
If I recall correctly, wasn't there a young man in the DR (Darryl Fornatora) whose friend left him behind. It has been thought he was killed (wallet washed ashore) but the DR police never really helped. I don't think solving crimes or putting attention on crimes is something the government wants. Here is his WS thread:
Dominican Republic - Darryl Fornatora, 46, FL man missing, 28 Jan 2016
If Portia was blond and 20-30, I think the papers would have heard about it. Portia was an older woman and a woman of color. I think she was mistaken for a local and not much time and effort given to finding out more about her.