Three brothers and a woman were gunned down at their homes in Masemure Meadows in Little London, Westmoreland Thursday morning.
The siblings have been identified as 23 year-old Shavane Humes, 29 year old Howard Humes and 33 year-old Paulton Humes.
The woman has been identified as 25 year-old Keneisha Wilson.
A five year old boy escaped injury.
The incident occurred about 1:15.
Superintendent Gary McKenzie, head of the Westmoreland police, said a police team was on patrol when it heard explosions coming from the housing scheme.
The police saw three one bedroom houses with the front doors open.
The bodies of the four individuals were found inside.
No motive has been established for the attack.
Superintendent McKenzie commented that Masemure Meadows largely consists of former sugar workers and has been peaceful.
He said one of the brothers was released from prison a year ago.