Two women believed to be a mother and daughter are dead and a male relative wounded.
The three have not yet been identified.
They were attacked in front of three young children in Chaguanas on Thursday night.
Police said the women, the man and the children were in a car at their home at Dynasty Drive, Joyce Road, Chaguanas.
As the car was reversing out of the driveway at around 7.20 pm, masked gunmen approached and shot at the mother and daughter.
The man in the car was injured.
Three girls, aged one, seven and eight, were in the car at the time. They were unharmed.
Neighbours heard the gunshots and called the police.
Members of the Central Division Task Force took the man to hospital. The three girls were taken into safekeeping.
Up to 9 pm police were still trying to confirm the names of the women.