chunk: After the cops arrive, Marcia explains that the dead body in the apartment was actually Lilian's rich sister, who bore a passing resemblance to Lilian but was not her twin. The sister had suffered a heart attack while visiting them, and the Houses decided to take advantage of the situation by claiming that it was Lilian who had died. Lilian would then assume the identity of her sister (a recluse living at the hotel) in order to manipulate her sister's will naming Lilian and Paul as sole beneficiaries. But Paul then double-crossed and killed Lilian, too, so he could run off with Helen.