omg i was thinking that, but maybe they were both at the scene, i think hs’s mum did kill the guy, she was the one who pushed him off, but because the guy that blackmailed her said he lost them for a bit, maybe the sister was the one who buried the body at the bottom of the cliff and not hs’s mum. cus both their hairs are similar length and everything the only thing different is the colour, but it’s dark anyway so it’s not like you can see the difference very clearly and the video is too blurry to make out anything specific, even heeseo said it was too blurry for him to claim it’s his mum
so my prediction is that maybe her sister’s baptist name is caecilia n hers is agatha. maybe her sis heeso’s aunt, killed someone but since they look so similar the guy thought it was her n threaten her. she knew that her sister was the one that killed someone but covered for her