Reading backwards from Ch. 62 to 57, it seems like the eldest sister accidentally killed the youngest brother when he SA'd her when she changed clothes in her room. She then collapsed on the floor due to shock. Then, the second sister heard the commotion, went to the room and saw the whole thing. She covered the whole incident up. The eldest sister completely forgets about this incident probably due to shockI went ahead and looked at the Raws, it should have 62 Chapters. Also...I believe it was an outside force that did the attempted murder, because he bags all 3 sisters