In season 1 of "The Sinner", Cora and Phoebes parents mention during one of the police interviews, that Cora ran away and Phoebe died one month later.
This doesn't make sense to me. At that point in time, Phoebe's body wasn't even found yet, so the parents never had proof that Phoebe actually died. When asked later, why they never reported the children missing, the mother simply stated that they thought both daughters ran away together. Again, they had no indication that Phoebe had died.
Cora could never have told them that Phoebe died, because she couldn't remember the night till the very end of season 1.
So I guess my question is: Did the parents know that Phoebe died, or did they simply assume the worst? If so, why the specific reference that she died "one month" after Cora ran away?