Cabarete beach is full of minors every night of the week, even more so when there are concerts such as Saturday night's one. It is quite normal for Dominican children to 'salir a bailar con mi prima' when they haven't even reached sixteen years old, yet alone eighteen! The Police do nothing about it whatsoever, they don't even arrest the shoe shine boys / vendedores de caracoles who are directly in contact with tourists anymore. Even some of the prostitutes that walk the beach at night brely look eighteen.
I don't know about 'another side of Cabarete being revealed' because if you take off your rose tinted glasses, the dark side has been out in the open for a long time.
Even though most of this situation happened in La Cienega a huge amount of inhabitants of La Cienaga, Callejon de las Lomas, El Play, Islabon and from even further afield are drawn to Cabarete's nightlife on a regular basis, and the culprits of this crime and every other crime that happens in the Cabarete area are probably from one of these particular areas.
Life is cheap here and although it may not have been the vengeful girl herself or her family a sicario would probably do the job for less than $500 anyway.
We'll have to see if anyone is brought to justice for this tragedy, but the likelihood is that the blame will be put on some local Haitian who will have been tortured/beaten until they admit to it and the real culprit will walk free.