The four that died were part of a 17-member group, which has been called the Hirwa family by the authorities.
"The potential of the three females for their contribution to the population was immense," (GVTC executive secretary Andrew) Seguya said.
He added that the 13 surviving members of the Hirwa family have been found and are feeding well.
image: "Mountain gorilla (Gorilla beringei beringei), 10 month old baby, Titus Group, Rwanda" by Charles J Sharp (CC BY-SA 4.0)