so we dont know if they were kept alive during the six months and killed before they were found ?
and we dont know if they were violated ?
is it also possible that they dont know how they died because of the state of bodies
It's possible that authorities weren't able to determine how they died due to the condition of the bodies, but I no longer think that is the case because of one of the recent (this year) interviews with investigators where one of them said that he, as a parent himself, would want to know how they died, so it kills him to keep that a secret from the families, but it would do more harm to the case to let that info out.
This interview is linked upthread.