Hi,
Normally it's the government of Comores
As they certainly not have a like NTSB or BEA (poor country) .. they will require a other authority for handle the investigations.
As french is language in Comores it's likely a french language country will be choice..
Maybe Canada .. but more likely the french BEA due to the French-Comores politics and economics relations + plane is french construction and the already stuff available in the region (Reunion island .. etc..)
IMHO
Bye.