Seems like y'all need to go the way of Martial Law.
Maybe some Jamaican brehs can clue me in on this, but it seems there's a level of systemic corruption that allows illicit guns, drugs etc to flow through the country unchecked. There are probably some big wigs in govt profiting off of the violence and chaos.
A country as small as Jamaica could easily become a mafia/cartel state if it's not already close. You need leadership willing to challenge those complicit and meet violence with violence. You need to be brutal with gang members and jail any corrupt official with long jail sentences.
Too many criminals to kill. It would send off the alarm for Human Rights watchers.
Also, Jamaica, like a lot of Caribbean islands are transshipment posts for cartels/mafias.
Also, the politicians pay gunmans to run the streets for them, protect them, intimidate, etc... Criminals are getting their power from the government.
This problem could be fixed very easily, but there isn't a political will to fix it.
Tl:dr
Jamaica is fukked for the foreseeable future. Stay away.